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2022-01-20RISC-V: Use __cpu_up_stack/task_pointer only for spinwait methodAtish Patra5-23/+30
The __cpu_up_stack/task_pointer array is only used for spinwait method now. The per cpu array based lookup is also fragile for platforms with discontiguous/sparse hartids. The spinwait method is only used for M-mode Linux or older firmwares without SBI HSM extension. For general Linux systems, ordered booting method is preferred anyways to support cpu hotplug and kexec. Make sure that __cpu_up_stack/task_pointer is only used for spinwait method. Take this opportunity to rename it to __cpu_spinwait_stack/task_pointer to emphasize the purpose as well. Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20RISC-V: Do not print the SBI version during HSM extension boot printAtish Patra1-1/+1
The HSM extension information log also prints the SBI version v0.2. This is misleading as the underlying firmware SBI version may be different from v0.2. Remove the unncessary printing of SBI version. Signed-off-by: Atish Patra <atishp@rivosinc.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20RISC-V: Avoid using per cpu array for ordered bootingAtish Patra4-15/+58
Currently both order booting and spinwait approach uses a per cpu array to update stack & task pointer. This approach will not work for the following cases. 1. If NR_CPUs are configured to be less than highest hart id. 2. A platform has sparse hartid. This issue can be fixed for ordered booting as the booting cpu brings up one cpu at a time using SBI HSM extension which has opaque parameter that is unused until now. Introduce a common secondary boot data structure that can store the stack and task pointer. Secondary harts will use this data while booting up to setup the sp & tp. Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: default to CONFIG_RISCV_SBI_V01=nHeinrich Schuchardt1-1/+0
The SBI 0.1 specification is obsolete. The current version is 0.3. Hence we should not rely by default on SBI 0.1 being implemented. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20arm64: mm: apply __ro_after_init to memory_limitPeng Fan1-1/+1
This variable is only set during initialization, so mark with __ro_after_init. Signed-off-by: Peng Fan <peng.fan@nxp.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20211215064559.2843555-1-peng.fan@oss.nxp.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-01-20arm64: atomics: lse: Dereference matching sizeKees Cook2-2/+2
When building with -Warray-bounds, the following warning is generated: In file included from ./arch/arm64/include/asm/lse.h:16, from ./arch/arm64/include/asm/cmpxchg.h:14, from ./arch/arm64/include/asm/atomic.h:16, from ./include/linux/atomic.h:7, from ./include/asm-generic/bitops/atomic.h:5, from ./arch/arm64/include/asm/bitops.h:25, from ./include/linux/bitops.h:33, from ./include/linux/kernel.h:22, from kernel/printk/printk.c:22: ./arch/arm64/include/asm/atomic_lse.h:247:9: warning: array subscript 'long unsigned int[0]' is partly outside array bounds of 'atomic_t[1]' [-Warray-bounds] 247 | asm volatile( \ | ^~~ ./arch/arm64/include/asm/atomic_lse.h:266:1: note: in expansion of macro '__CMPXCHG_CASE' 266 | __CMPXCHG_CASE(w, , acq_, 32, a, "memory") | ^~~~~~~~~~~~~~ kernel/printk/printk.c:3606:17: note: while referencing 'printk_cpulock_owner' 3606 | static atomic_t printk_cpulock_owner = ATOMIC_INIT(-1); | ^~~~~~~~~~~~~~~~~~~~ This is due to the compiler seeing an unsigned long * cast against something (atomic_t) that is int sized. Replace the cast with the matching size cast. This results in no change in binary output. Note that __ll_sc__cmpxchg_case_##name##sz already uses the same constraint: [v] "+Q" (*(u##sz *)ptr Which is why only the LSE form needs updating and not the LL/SC form, so this change is unlikely to be problematic. Cc: Will Deacon <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: linux-arm-kernel@lists.infradead.org Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220112202259.3950286-1-keescook@chromium.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-01-20Merge tag 'net-5.17-rc1' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Jakub Kicinski: "Including fixes from netfilter, bpf. Quite a handful of old regression fixes but most of those are pre-5.16. Current release - regressions: - fix memory leaks in the skb free deferral scheme if upper layer protocols are used, i.e. in-kernel TCP readers like TLS Current release - new code bugs: - nf_tables: fix NULL check typo in _clone() functions - change the default to y for Vertexcom vendor Kconfig - a couple of fixes to incorrect uses of ref tracking - two fixes for constifying netdev->dev_addr Previous releases - regressions: - bpf: - various verifier fixes mainly around register offset handling when passed to helper functions - fix mount source displayed for bpffs (none -> bpffs) - bonding: - fix extraction of ports for connection hash calculation - fix bond_xmit_broadcast return value when some devices are down - phy: marvell: add Marvell specific PHY loopback - sch_api: don't skip qdisc attach on ingress, prevent ref leak - htb: restore minimal packet size handling in rate control - sfp: fix high power modules without diagnostic monitoring - mscc: ocelot: - don't let phylink re-enable TX PAUSE on the NPI port - don't dereference NULL pointers with shared tc filters - smsc95xx: correct reset handling for LAN9514 - cpsw: avoid alignment faults by taking NET_IP_ALIGN into account - phy: micrel: use kszphy_suspend/_resume for irq aware devices, avoid races with the interrupt Previous releases - always broken: - xdp: check prog type before updating BPF link - smc: resolve various races around abnormal connection termination - sit: allow encapsulated IPv6 traffic to be delivered locally - axienet: fix init/reset handling, add missing barriers, read the right status words, stop queues correctly - add missing dev_put() in sock_timestamping_bind_phc() Misc: - ipv4: prevent accidentally passing RTO_ONLINK to ip_route_output_key_hash() by sanitizing flags - ipv4: avoid quadratic behavior in netns dismantle - stmmac: dwmac-oxnas: add support for OX810SE - fsl: xgmac_mdio: add workaround for erratum A-009885" * tag 'net-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (92 commits) ipv4: add net_hash_mix() dispersion to fib_info_laddrhash keys ipv4: avoid quadratic behavior in netns dismantle net/fsl: xgmac_mdio: Fix incorrect iounmap when removing module powerpc/fsl/dts: Enable WA for erratum A-009885 on fman3l MDIO buses dt-bindings: net: Document fsl,erratum-a009885 net/fsl: xgmac_mdio: Add workaround for erratum A-009885 net: mscc: ocelot: fix using match before it is set net: phy: micrel: use kszphy_suspend()/kszphy_resume for irq aware devices net: cpsw: avoid alignment faults by taking NET_IP_ALIGN into account nfc: llcp: fix NULL error pointer dereference on sendmsg() after failed bind() net: axienet: increase default TX ring size to 128 net: axienet: fix for TX busy handling net: axienet: fix number of TX ring slots for available check net: axienet: Fix TX ring slot available check net: axienet: limit minimum TX ring size net: axienet: add missing memory barriers net: axienet: reset core on initialization prior to MDIO access net: axienet: Wait for PhyRstCmplt after core reset net: axienet: increase reset timeout bpf, selftests: Add ringbuf memory type confusion test ...
2022-01-20Merge branch 'akpm' (patches from Andrew)Linus Torvalds13-339/+50
Merge more updates from Andrew Morton: "55 patches. Subsystems affected by this patch series: percpu, procfs, sysctl, misc, core-kernel, get_maintainer, lib, checkpatch, binfmt, nilfs2, hfs, fat, adfs, panic, delayacct, kconfig, kcov, and ubsan" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (55 commits) lib: remove redundant assignment to variable ret ubsan: remove CONFIG_UBSAN_OBJECT_SIZE kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB btrfs: use generic Kconfig option for 256kB page size limit arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KB configs: introduce debug.config for CI-like setup delayacct: track delays from memory compact Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact delayacct: cleanup flags in struct task_delay_info and functions use it delayacct: fix incomplete disable operation when switch enable to disable delayacct: support swapin delay accounting for swapping without blkio panic: remove oops_id panic: use error_report_end tracepoint on warnings fs/adfs: remove unneeded variable make code cleaner FAT: use io_schedule_timeout() instead of congestion_wait() hfsplus: use struct_group_attr() for memcpy() region nilfs2: remove redundant pointer sbufs fs/binfmt_elf: use PT_LOAD p_align values for static PIE const_structs.checkpatch: add frequently used ops structs ...
2022-01-20kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTRMarco Elver1-1/+1
Until recent versions of GCC and Clang, it was not possible to disable KCOV instrumentation via a function attribute. The relevant function attribute was introduced in 540540d06e9d9 ("kcov: add __no_sanitize_coverage to fix noinstr for all architectures"). x86 was the first architecture to want a working noinstr, and at the time no compiler support for the attribute existed yet. Therefore, commit 0f1441b44e823 ("objtool: Fix noinstr vs KCOV") introduced the ability to NOP __sanitizer_cov_*() calls in .noinstr.text. However, this doesn't work for other architectures like arm64 and s390 that want a working noinstr per ARCH_WANTS_NO_INSTR. At the time of 0f1441b44e823, we didn't yet have ARCH_WANTS_NO_INSTR, but now we can move the Kconfig dependency checks to the generic KCOV option. KCOV will be available if: - architecture does not care about noinstr, OR - we have objtool support (like on x86), OR - GCC is 12.0 or newer, OR - Clang is 13.0 or newer. Link: https://lkml.kernel.org/r/20211201152604.3984495-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KBNathan Chancellor1-0/+4
Patch series "Fix CONFIG_TEST_KMOD with 256kB page size". The kernel test robot reported a build error [1] from a failed assertion in fs/btrfs/inode.c with a hexagon randconfig that includes CONFIG_PAGE_SIZE_256KB. This error is the same one that was addressed by commit b05fbcc36be1 ("btrfs: disable build on platforms having page size 256K") but CONFIG_TEST_KMOD selects CONFIG_BTRFS without having the "page size less than 256kB dependency", which results in the error reappearing. The first patch introduces CONFIG_PAGE_SIZE_LESS_THAN_256KB by splitting it off from CONFIG_PAGE_SIZE_LESS_THAN_64KB, which was introduced in commit 1f0e290cc5fd ("arch: Add generic Kconfig option indicating page size smaller than 64k") for a similar reason in 5.16-rc3. The second patch uses that configuration option for CONFIG_BTRFS to reduce duplication. The third patch resolves the build error by adding CONFIG_PAGE_SIZE_LESS_THAN_256KB as a dependency to CONFIG_TEST_KMOD so that CONFIG_BTRFS does not get enabled under that invalid configuration. [1]: https://lore.kernel.org/r/202111270255.UYOoN5VN-lkp@intel.com/ This patch (of 3): btrfs requires a page size smaller than 256kB. To use that dependency in other places, introduce CONFIG_PAGE_SIZE_LESS_THAN_256KB and reuse that dependency in CONFIG_PAGE_SIZE_LESS_THAN_64KB. Link: https://lkml.kernel.org/r/20211129230141.228085-1-nathan@kernel.org Link: https://lkml.kernel.org/r/20211129230141.228085-2-nathan@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: David Sterba <dsterba@suse.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20proc: make the proc_create[_data]() stubs static inlinesHans de Goede1-5/+3
Change the proc_create[_data]() stubs which are used when CONFIG_PROC_FS is not set from #defines to a static inline stubs. This should fix clang -Werror builds failing due to errors like this: drivers/platform/x86/thinkpad_acpi.c:918:30: error: unused variable 'dispatch_proc_ops' [-Werror,-Wunused-const-variable] Fixing this in include/linux/proc_fs.h should ensure that the same issue is also fixed in any other drivers hitting the same -Werror issue. [akpm@linux-foundation.org: fix CONFIG_PROC_FS=n] [akpm@linux-foundation.org: fix arch/sparc/kernel/led.c] [akpm@linux-foundation.org: fix build] Link: https://lkml.kernel.org/r/20211116131112.508304-1-hdegoede@redhat.com Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reported-by: kernel test robot <lkp@intel.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Hans de Goede <hdegoede@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20mm: percpu: add generic pcpu_populate_pte() functionKefeng Wang3-104/+4
With NEED_PER_CPU_PAGE_FIRST_CHUNK enabled, we need a function to populate pte, this patch adds a generic pcpu populate pte function, pcpu_populate_pte(), which is marked __weak and used on most architectures, but it is overridden on x86, which has its own implementation. Link: https://lkml.kernel.org/r/20211216112359.103822-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Dennis Zhou <dennis@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20mm: percpu: add generic pcpu_fc_alloc/free funcitonKefeng Wang4-171/+5
With the previous patch, we could add a generic pcpu first chunk allocate and free function to cleanup the duplicated definations on each architecture. Link: https://lkml.kernel.org/r/20211216112359.103822-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Dennis Zhou <dennis@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20mm: percpu: add pcpu_fc_cpu_to_node_fn_t typedefKefeng Wang4-15/+43
Add pcpu_fc_cpu_to_node_fn_t and pass it into pcpu_fc_alloc_fn_t, pcpu first chunk allocation will call it to alloc memblock on the corresponding node by it, this is prepare for the next patch. Link: https://lkml.kernel.org/r/20211216112359.103822-3-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Dennis Zhou <dennis@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20mm: percpu: generalize percpu related configKefeng Wang7-74/+21
Patch series "mm: percpu: Cleanup percpu first chunk function". When supporting page mapping percpu first chunk allocator on arm64, we found there are lots of duplicated codes in percpu embed/page first chunk allocator. This patchset is aimed to cleanup them and should no function change. The currently supported status about 'embed' and 'page' in Archs shows below, embed: NEED_PER_CPU_PAGE_FIRST_CHUNK page: NEED_PER_CPU_EMBED_FIRST_CHUNK embed page ------------------------ arm64 Y Y mips Y N powerpc Y Y riscv Y N sparc Y Y x86 Y Y ------------------------ There are two interfaces about percpu first chunk allocator, extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size, size_t atom_size, pcpu_fc_cpu_distance_fn_t cpu_distance_fn, - pcpu_fc_alloc_fn_t alloc_fn, - pcpu_fc_free_fn_t free_fn); + pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn); extern int __init pcpu_page_first_chunk(size_t reserved_size, - pcpu_fc_alloc_fn_t alloc_fn, - pcpu_fc_free_fn_t free_fn, - pcpu_fc_populate_pte_fn_t populate_pte_fn); + pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn); The pcpu_fc_alloc_fn_t/pcpu_fc_free_fn_t is killed, we provide generic pcpu_fc_alloc() and pcpu_fc_free() function, which are called in the pcpu_embed/page_first_chunk(). 1) For pcpu_embed_first_chunk(), pcpu_fc_cpu_to_node_fn_t is needed to be provided when archs supported NUMA. 2) For pcpu_page_first_chunk(), the pcpu_fc_populate_pte_fn_t is killed too, a generic pcpu_populate_pte() which marked '__weak' is provided, if you need a different function to populate pte on the arch(like x86), please provide its own implementation. [1] https://github.com/kevin78/linux.git percpu-cleanup This patch (of 4): The HAVE_SETUP_PER_CPU_AREA/NEED_PER_CPU_EMBED_FIRST_CHUNK/ NEED_PER_CPU_PAGE_FIRST_CHUNK/USE_PERCPU_NUMA_NODE_ID configs, which have duplicate definitions on platforms that subscribe it. Move them into mm, drop these redundant definitions and instead just select it on applicable platforms. Link: https://lkml.kernel.org/r/20211216112359.103822-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20211216112359.103822-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Cc: Will Deacon <will@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20riscv: fix boolconv.cocci warningskernel test robot1-2/+1
arch/riscv/mm/init.c:48:11-16: WARNING: conversion to bool not needed here Remove unneeded conversion to bool Semantic patch information: Relational and logical operators evaluate to bool, explicit conversion is overly verbose and unneeded. Generated by: scripts/coccinelle/misc/boolconv.cocci Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: kernel test robot <lkp@intel.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20RISC-V: Introduce sv48 support without relocatable kernelPalmer Dabbelt17-188/+705
This patchset allows to have a single kernel for sv39 and sv48 without being relocatable. The idea comes from Arnd Bergmann who suggested to do the same as x86, that is mapping the kernel to the end of the address space, which allows the kernel to be linked at the same address for both sv39 and sv48 and then does not require to be relocated at runtime. This implements sv48 support at runtime. The kernel will try to boot with 4-level page table and will fallback to 3-level if the HW does not support it. Folding the 4th level into a 3-level page table has almost no cost at runtime. Note that kasan region had to be moved to the end of the address space since its location must be known at compile-time and then be valid for both sv39 and sv48 (and sv57 that is coming). * riscv-sv48-v3: riscv: Explicit comment about user virtual address space size riscv: Use pgtable_l4_enabled to output mmu_type in cpuinfo riscv: Implement sv48 support asm-generic: Prepare for riscv use of pud_alloc_one and pud_free riscv: Allow to dynamically define VA_BITS riscv: Introduce functions to switch pt_ops riscv: Split early kasan mapping to prepare sv48 introduction riscv: Move KASAN mapping next to the kernel mapping riscv: Get rid of MAXPHYSMEM configs Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Explicit comment about user virtual address space sizeAlexandre Ghiti1-0/+9
Define precisely the size of the user accessible virtual space size for sv32/39/48 mmu types and explain why the whole virtual address space is split into 2 equal chunks between kernel and user space. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Use pgtable_l4_enabled to output mmu_type in cpuinfoAlexandre Ghiti1-11/+12
Now that the mmu type is determined at runtime using SATP characteristic, use the global variable pgtable_l4_enabled to output mmu type of the processor through /proc/cpuinfo instead of relying on device tree infos. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Implement sv48 supportAlexandre Ghiti12-44/+512
By adding a new 4th level of page table, give the possibility to 64bit kernel to address 2^48 bytes of virtual address: in practice, that offers 128TB of virtual address space to userspace and allows up to 64TB of physical memory. If the underlying hardware does not support sv48, we will automatically fallback to a standard 3-level page table by folding the new PUD level into PGDIR level. In order to detect HW capabilities at runtime, we use SATP feature that ignores writes with an unsupported mode. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Allow to dynamically define VA_BITSAlexandre Ghiti4-14/+14
With 4-level page table folding at runtime, we don't know at compile time the size of the virtual address space so we must set VA_BITS dynamically so that sparsemem reserves the right amount of memory for struct pages. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Introduce functions to switch pt_opsAlexandre Ghiti1-23/+51
This simply gathers the different pt_ops initialization in functions where a comment was added to explain why the page table operations must be changed along the boot process. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Split early kasan mapping to prepare sv48 introductionAlexandre Ghiti3-51/+67
Now that kasan shadow region is next to the kernel, for sv48, this region won't be aligned on PGDIR_SIZE and then when populating this region, we'll need to get down to lower levels of the page table. So instead of reimplementing the page table walk for the early population, take advantage of the existing functions used for the final population. Note that kasan swapper initialization must also be split since memblock is not initialized at this point and as the last PGD is shared with the kernel, we'd need to allocate a PUD so postpone the kasan final population after the kernel population is done. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Move KASAN mapping next to the kernel mappingAlexandre Ghiti5-25/+32
Now that KASAN_SHADOW_OFFSET is defined at compile time as a config, this value must remain constant whatever the size of the virtual address space, which is only possible by pushing this region at the end of the address space next to the kernel mapping. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Get rid of MAXPHYSMEM configsAlexandre Ghiti4-26/+2
CONFIG_MAXPHYSMEM_* are actually never used, even the nommu defconfigs selecting the MAXPHYSMEM_2GB had no effects on PAGE_OFFSET since it was preempted by !MMU case right before. In addition, the move of the kernel mapping at the end of the address space broke the use of MAXPHYSMEM_2G with MMU since it defines PAGE_OFFSET at the same address as the kernel mapping. Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Fixes: 2bfc6cd81bd1 ("riscv: Move kernel mapping outside of linear mapping") Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Conor Dooley <Conor.Dooley@microchip.com> Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-19riscv: bpf: Fix eBPF's exception tablesJisheng Zhang1-1/+1
eBPF's exception tables needs to be modified to relative synchronously. Suggested-by: Tong Tiangen <tongtiangen@huawei.com> Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Fixes: 1f77ed9422cb ("riscv: switch to relative extable and other improvements") Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-19riscv: mm: init: try best to remove #ifdef CONFIG_XIP_KERNEL usageJisheng Zhang1-8/+3
Currently, the #ifdef CONFIG_XIP_KERNEL usage can be divided into the following three types: The first one is for functions/declarations only used in XIP case. The second one is for XIP_FIXUP case. Something as below: |foo_type foo; |#ifdef CONFIG_XIP_KERNEL |#define foo (*(foo_type *)XIP_FIXUP(&foo)) |#endif Usually, it's better to let the foo macro sit with the foo var together. But if various foos are defined adjacently, we can save some #ifdef CONFIG_XIP_KERNEL usage by grouping them together. The third one is for different implementations for XIP, usually, this is a #ifdef...#else...#endif case. This patch moves the pt_ops macro to adjacent #ifdef CONFIG_XIP_KERNEL and group first type usage cases into one. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-19riscv: mm: init: try IS_ENABLED(CONFIG_XIP_KERNEL) instead of #ifdefJisheng Zhang1-9/+7
Try our best to replace the conditional compilation using "#ifdef CONFIG_XIP_KERNEL" with "IS_ENABLED(CONFIG_XIP_KERNEL)", to simplify the code and to increase compile coverage. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-19riscv: mm: init: remove _pt_ops and use pt_ops directlyJisheng Zhang1-4/+2
Except "pt_ops", other global vars when CONFIG_XIP_KERNEL=y is defined as below: |foo_type foo; |#ifdef CONFIG_XIP_KERNEL |#define foo (*(foo_type *)XIP_FIXUP(&foo)) |#endif Follow the same way for pt_ops to unify the style and to simplify code. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-19riscv: mm: init: try best to use IS_ENABLED(CONFIG_64BIT) instead of #ifdefJisheng Zhang1-27/+16
Try our best to replace the conditional compilation using "#ifdef CONFIG_64BIT" by a check for "IS_ENABLED(CONFIG_64BIT)", to simplify the code and to increase compile coverage. Now we can also remove the __maybe_unused used in max_mapped_addr declaration. We also remove the BUG_ON check of mapping the last 4K bytes of the addressable memory since this is always true for every kernel actually. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-19riscv: mm: init: remove unnecessary "#ifdef CONFIG_CRASH_DUMP"Jisheng Zhang1-2/+0
The is_kdump_kernel() returns false for !CRASH_DUMP case, so we don't need the #ifdef CONFIG_CRASH_DUMP for is_kdump_kernel() checking. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Alexandre Ghiti <alex@ghiti.fr> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-19KVM: SVM: Nullify vcpu_(un)blocking() hooks if AVIC is disabledSean Christopherson3-6/+9
Nullify svm_x86_ops.vcpu_(un)blocking if AVIC/APICv is disabled as the hooks are necessary only to clear the vCPU's IsRunning entry in the Physical APIC and to update IRTE entries if the VM has a pass-through device attached. Opportunistically rename the helpers to clarify their AVIC relationship. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211208015236.1616697-24-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: SVM: Move svm_hardware_setup() and its helpers below svm_x86_opsSean Christopherson1-233/+234
Move svm_hardware_setup() below svm_x86_ops so that KVM can modify ops during setup, e.g. the vcpu_(un)blocking hooks can be nullified if AVIC is disabled or unsupported. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211208015236.1616697-23-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: SVM: Drop AVIC's intermediate avic_set_running() helperSean Christopherson1-20/+36
Drop avic_set_running() in favor of calling avic_vcpu_{load,put}() directly, and modify the block+put path to use preempt_disable/enable() instead of get/put_cpu(), as it doesn't actually care about the current pCPU associated with the vCPU. Opportunistically add lockdep assertions as being preempted in avic_vcpu_put() would lead to consuming stale data, even though doing so _in the current code base_ would not be fatal. Add a much needed comment explaining why svm_vcpu_blocking() needs to unload the AVIC and update the IRTE _before_ the vCPU starts blocking. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211208015236.1616697-22-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: VMX: Don't do full kick when handling posted interrupt wakeupSean Christopherson1-1/+1
When waking vCPUs in the posted interrupt wakeup handling, do exactly that and no more. There is no need to kick the vCPU as the wakeup handler just needs to get the vCPU task running, and if it's in the guest then it's definitely running. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-21-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: VMX: Fold fallback path into triggering posted IRQ helperSean Christopherson1-8/+10
Move the fallback "wake_up" path into the helper to trigger posted interrupt helper now that the nested and non-nested paths are identical. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-20-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: VMX: Pass desired vector instead of bool for triggering posted IRQSean Christopherson1-5/+3
Refactor the posted interrupt helper to take the desired notification vector instead of a bool so that the callers are self-documenting. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-19-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: VMX: Don't do full kick when triggering posted interrupt "fails"Sean Christopherson2-6/+7
Replace the full "kick" with just the "wake" in the fallback path when triggering a virtual interrupt via a posted interrupt fails because the guest is not IN_GUEST_MODE. If the guest transitions into guest mode between the check and the kick, then it's guaranteed to see the pending interrupt as KVM syncs the PIR to IRR (and onto GUEST_RVI) after setting IN_GUEST_MODE. Kicking the guest in this case is nothing more than an unnecessary VM-Exit (and host IRQ). Opportunistically update comments to explain the various ordering rules and barriers at play. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211208015236.1616697-17-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: SVM: Skip AVIC and IRTE updates when loading blocking vCPUSean Christopherson1-14/+18
Don't bother updating the Physical APIC table or IRTE when loading a vCPU that is blocking, i.e. won't be marked IsRun{ning}=1, as the pCPU is queried if and only if IsRunning is '1'. If the vCPU was migrated, the new pCPU will be picked up when avic_vcpu_load() is called by svm_vcpu_unblocking(). Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211208015236.1616697-15-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: SVM: Use kvm_vcpu_is_blocking() in AVIC load to handle preemptionSean Christopherson3-12/+9
Use kvm_vcpu_is_blocking() to determine whether or not the vCPU should be marked running during avic_vcpu_load(). Drop avic_is_running, which really should have been named "vcpu_is_not_blocking", as it tracked if the vCPU was blocking, not if it was actually running, e.g. it was set during svm_create_vcpu() when the vCPU was obviously not running. This is technically a teeny tiny functional change, as the vCPU will be marked IsRunning=1 on being reloaded if the vCPU is preempted between svm_vcpu_blocking() and prepare_to_rcuwait(). But that's a benign change as the vCPU will be marked IsRunning=0 when KVM voluntarily schedules out the vCPU. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211208015236.1616697-14-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: SVM: Remove unnecessary APICv/AVIC update in vCPU unblocking pathSean Christopherson1-2/+0
Remove handling of KVM_REQ_APICV_UPDATE from svm_vcpu_unblocking(), it's no longer needed as it was made obsolete by commit df7e4827c549 ("KVM: SVM: call avic_vcpu_load/avic_vcpu_put when enabling/disabling AVIC"). Prior to that commit, the manual check was necessary to ensure the AVIC stuff was updated by avic_set_running() when a request to enable APICv became pending while the vCPU was blocking, as the request handling itself would not do the update. But, as evidenced by the commit, that logic was flawed and subject to various races. Now that svm_refresh_apicv_exec_ctrl() does avic_vcpu_load/put() in response to an APICv status change, drop the manual check in the unblocking path. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211208015236.1616697-13-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: SVM: Don't bother checking for "running" AVIC when kicking for IPIsSean Christopherson2-17/+9
Drop the avic_vcpu_is_running() check when waking vCPUs in response to a VM-Exit due to incomplete IPI delivery. The check isn't wrong per se, but it's not 100% accurate in the sense that it doesn't guarantee that the vCPU was one of the vCPUs that didn't receive the IPI. The check isn't required for correctness as blocking == !running in this context. From a performance perspective, waking a live task is not expensive as the only moderately costly operation is a locked operation to temporarily disable preemption. And if that is indeed a performance issue, kvm_vcpu_is_blocking() would be a better check than poking into the AVIC. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-12-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: SVM: Signal AVIC doorbell iff vCPU is in guest modeSean Christopherson1-2/+20
Signal the AVIC doorbell iff the vCPU is running in the guest. If the vCPU is not IN_GUEST_MODE, it's guaranteed to pick up any pending IRQs on the next VMRUN, which unconditionally processes the vIRR. Add comments to document the logic. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211208015236.1616697-11-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: x86: Remove defunct pre_block/post_block kvm_x86_ops hooksSean Christopherson4-32/+1
Drop kvm_x86_ops' pre/post_block() now that all implementations are nops. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-10-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: x86: Unexport LAPIC's switch_to_{hv,sw}_timer() helpersSean Christopherson1-2/+0
Unexport switch_to_{hv,sw}_timer() now that common x86 handles the transitions. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-9-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: VMX: Move preemption timer <=> hrtimer dance to common x86Sean Christopherson2-5/+22
Handle the switch to/from the hypervisor/software timer when a vCPU is blocking in common x86 instead of in VMX. Even though VMX is the only user of a hypervisor timer, the logic and all functions involved are generic x86 (unless future CPUs do something completely different and implement a hypervisor timer that runs regardless of mode). Handling the switch in common x86 will allow for the elimination of the pre/post_blocks hooks, and also lets KVM switch back to the hypervisor timer if and only if it was in use (without additional params). Add a comment explaining why the switch cannot be deferred to kvm_sched_out() or kvm_vcpu_block(). Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-8-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: Move x86 VMX's posted interrupt list_head to vcpu_vmxSean Christopherson3-19/+25
Move the seemingly generic block_vcpu_list from kvm_vcpu to vcpu_vmx, and rename the list and all associated variables to clarify that it tracks the set of vCPU that need to be poked on a posted interrupt to the wakeup vector. The list is not used to track _all_ vCPUs that are blocking, and the term "blocked" can be misleading as it may refer to a blocking condition in the host or the guest, where as the PI wakeup case is specifically for the vCPUs that are actively blocking from within the guest. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-7-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: VMX: Handle PI descriptor updates during vcpu_put/loadSean Christopherson3-93/+70
Move the posted interrupt pre/post_block logic into vcpu_put/load respectively, using the kvm_vcpu_is_blocking() to determining whether or not the wakeup handler needs to be set (and unset). This avoids updating the PI descriptor if halt-polling is successful, reduces the number of touchpoints for updating the descriptor, and eliminates the confusing behavior of intentionally leaving a "stale" PI.NDST when a blocking vCPU is scheduled back in after preemption. The downside is that KVM will do the PID update twice if the vCPU is preempted after prepare_to_rcuwait() but before schedule(), but that's a rare case (and non-existent on !PREEMPT kernels). The notable wart is the need to send a self-IPI on the wakeup vector if an outstanding notification is pending after configuring the wakeup vector. Ideally, KVM would just do a kvm_vcpu_wake_up() in this case, but the scheduler doesn't support waking a task from its preemption notifier callback, i.e. while the task is right in the middle of being scheduled out. Note, setting the wakeup vector before halt-polling is not necessary: once the pending IRQ will be recorded in the PIR, kvm_vcpu_has_events() will detect this (via kvm_cpu_get_interrupt(), kvm_apic_get_interrupt(), apic_has_interrupt_for_ppr() and finally vmx_sync_pir_to_irr()) and terminate the polling. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20211208015236.1616697-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19Merge branch 'kvm-pi-raw-spinlock' into HEADPaolo Bonzini68-214/+314
Bring in fix for VT-d posted interrupts before further changing the code in 5.17. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-19KVM: VMX: Reject KVM_RUN if emulation is required with pending exceptionSean Christopherson5-5/+37
Reject KVM_RUN if emulation is required (because VMX is running without unrestricted guest) and an exception is pending, as KVM doesn't support emulating exceptions except when emulating real mode via vm86. The vCPU is hosed either way, but letting KVM_RUN proceed triggers a WARN due to the impossible condition. Alternatively, the WARN could be removed, but then userspace and/or KVM bugs would result in the vCPU silently running in a bad state, which isn't very friendly to users. Originally, the bug was hit by syzkaller with a nested guest as that doesn't require kvm_intel.unrestricted_guest=0. That particular flavor is likely fixed by commit cd0e615c49e5 ("KVM: nVMX: Synthesize TRIPLE_FAULT for L2 if emulation is required"), but it's trivial to trigger the WARN with a non-nested guest, and userspace can likely force bad state via ioctls() for a nested guest as well. Checking for the impossible condition needs to be deferred until KVM_RUN because KVM can't force specific ordering between ioctls. E.g. clearing exception.pending in KVM_SET_SREGS doesn't prevent userspace from setting it in KVM_SET_VCPU_EVENTS, and disallowing KVM_SET_VCPU_EVENTS with emulation_required would prevent userspace from queuing an exception and then stuffing sregs. Note, if KVM were to try and detect/prevent the condition prior to KVM_RUN, handle_invalid_guest_state() and/or handle_emulation_failure() would need to be modified to clear the pending exception prior to exiting to userspace. ------------[ cut here ]------------ WARNING: CPU: 6 PID: 137812 at arch/x86/kvm/vmx/vmx.c:1623 vmx_queue_exception+0x14f/0x160 [kvm_intel] CPU: 6 PID: 137812 Comm: vmx_invalid_nes Not tainted 5.15.2-7cc36c3e14ae-pop #279 Hardware name: ASUS Q87M-E/Q87M-E, BIOS 1102 03/03/2014 RIP: 0010:vmx_queue_exception+0x14f/0x160 [kvm_intel] Code: <0f> 0b e9 fd fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 RSP: 0018:ffffa45c83577d38 EFLAGS: 00010202 RAX: 0000000000000003 RBX: 0000000080000006 RCX: 0000000000000006 RDX: 0000000000000000 RSI: 0000000000010002 RDI: ffff9916af734000 RBP: ffff9916af734000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000006 R13: 0000000000000000 R14: ffff9916af734038 R15: 0000000000000000 FS: 00007f1e1a47c740(0000) GS:ffff99188fb80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1e1a6a8008 CR3: 000000026f83b005 CR4: 00000000001726e0 Call Trace: kvm_arch_vcpu_ioctl_run+0x13a2/0x1f20 [kvm] kvm_vcpu_ioctl+0x279/0x690 [kvm] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported-by: syzbot+82112403ace4cbd780d8@syzkaller.appspotmail.com Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211228232437.1875318-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>