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authorLinus Torvalds <torvalds@linux-foundation.org>2019-11-26 05:02:36 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-11-26 05:02:36 +0300
commit752272f16dd18f2cac58a583a8673c8e2fb93abb (patch)
tree1a2bae3067e1133c1d1b8e0bbbaea8c34e3321b2 /Documentation
parent3f3c8be973af10875cfa1e7b85a535b6ba76b44f (diff)
parent96710247298df52a4b8150a62a6fe87083093ff3 (diff)
downloadlinux-752272f16dd18f2cac58a583a8673c8e2fb93abb.tar.xz
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini: "ARM: - data abort report and injection - steal time support - GICv4 performance improvements - vgic ITS emulation fixes - simplify FWB handling - enable halt polling counters - make the emulated timer PREEMPT_RT compliant s390: - small fixes and cleanups - selftest improvements - yield improvements PPC: - add capability to tell userspace whether we can single-step the guest - improve the allocation of XIVE virtual processor IDs - rewrite interrupt synthesis code to deliver interrupts in virtual mode when appropriate. - minor cleanups and improvements. x86: - XSAVES support for AMD - more accurate report of nested guest TSC to the nested hypervisor - retpoline optimizations - support for nested 5-level page tables - PMU virtualization optimizations, and improved support for nested PMU virtualization - correct latching of INITs for nested virtualization - IOAPIC optimization - TSX_CTRL virtualization for more TAA happiness - improved allocation and flushing of SEV ASIDs - many bugfixes and cleanups" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (127 commits) kvm: nVMX: Relax guest IA32_FEATURE_CONTROL constraints KVM: x86: Grab KVM's srcu lock when setting nested state KVM: x86: Open code shared_msr_update() in its only caller KVM: Fix jump label out_free_* in kvm_init() KVM: x86: Remove a spurious export of a static function KVM: x86: create mmu/ subdirectory KVM: nVMX: Remove unnecessary TLB flushes on L1<->L2 switches when L1 use apic-access-page KVM: x86: remove set but not used variable 'called' KVM: nVMX: Do not mark vmcs02->apic_access_page as dirty when unpinning KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it KVM: vmx: implement MSR_IA32_TSX_CTRL disable RTM functionality KVM: x86: implement MSR_IA32_TSX_CTRL effect on CPUID KVM: x86: do not modify masked bits of shared MSRs KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES KVM: PPC: Book3S HV: XIVE: Fix potential page leak on error path KVM: PPC: Book3S HV: XIVE: Free previous EQ page when setting up a new one KVM: nVMX: Assume TLB entries of L1 and L2 are tagged differently if L0 use EPT KVM: x86: Unexport kvm_vcpu_reload_apic_access_page() KVM: nVMX: add CR4_LA57 bit to nested CR4_FIXED1 KVM: nVMX: Use semi-colon instead of comma for exit-handlers initialization ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt6
-rw-r--r--Documentation/virt/kvm/api.txt58
-rw-r--r--Documentation/virt/kvm/arm/pvtime.rst80
-rw-r--r--Documentation/virt/kvm/devices/vcpu.txt14
-rw-r--r--Documentation/virt/kvm/devices/xics.txt14
-rw-r--r--Documentation/virt/kvm/devices/xive.txt8
6 files changed, 174 insertions, 6 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 8dee8f68fe15..9b847f06cb19 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3110,9 +3110,9 @@
[X86,PV_OPS] Disable paravirtualized VMware scheduler
clock and use the default one.
- no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
- steal time is computed, but won't influence scheduler
- behaviour
+ no-steal-acc [X86,KVM,ARM64] Disable paravirtualized steal time
+ accounting. steal time is computed, but won't
+ influence scheduler behaviour
nolapic [X86-32,APIC] Do not enable or use the local APIC.
diff --git a/Documentation/virt/kvm/api.txt b/Documentation/virt/kvm/api.txt
index 4833904d32a5..49183add44e7 100644
--- a/Documentation/virt/kvm/api.txt
+++ b/Documentation/virt/kvm/api.txt
@@ -1002,12 +1002,18 @@ Specifying exception.has_esr on a system that does not support it will return
-EINVAL. Setting anything other than the lower 24bits of exception.serror_esr
will return -EINVAL.
+It is not possible to read back a pending external abort (injected via
+KVM_SET_VCPU_EVENTS or otherwise) because such an exception is always delivered
+directly to the virtual CPU).
+
+
struct kvm_vcpu_events {
struct {
__u8 serror_pending;
__u8 serror_has_esr;
+ __u8 ext_dabt_pending;
/* Align it to 8 bytes */
- __u8 pad[6];
+ __u8 pad[5];
__u64 serror_esr;
} exception;
__u32 reserved[12];
@@ -1051,9 +1057,23 @@ contain a valid state and shall be written into the VCPU.
ARM/ARM64:
+User space may need to inject several types of events to the guest.
+
Set the pending SError exception state for this VCPU. It is not possible to
'cancel' an Serror that has been made pending.
+If the guest performed an access to I/O memory which could not be handled by
+userspace, for example because of missing instruction syndrome decode
+information or because there is no device mapped at the accessed IPA, then
+userspace can ask the kernel to inject an external abort using the address
+from the exiting fault on the VCPU. It is a programming error to set
+ext_dabt_pending after an exit which was not either KVM_EXIT_MMIO or
+KVM_EXIT_ARM_NISV. This feature is only available if the system supports
+KVM_CAP_ARM_INJECT_EXT_DABT. This is a helper which provides commonality in
+how userspace reports accesses for the above cases to guests, across different
+userspace implementations. Nevertheless, userspace can still emulate all Arm
+exceptions by manipulating individual registers using the KVM_SET_ONE_REG API.
+
See KVM_GET_VCPU_EVENTS for the data structure.
@@ -2982,6 +3002,9 @@ can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and
KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number
indicating the number of supported registers.
+For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether
+the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported.
+
When debug events exit the main run loop with the reason
KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run
structure containing architecture specific debug information.
@@ -4468,6 +4491,39 @@ Hyper-V SynIC state change. Notification is used to remap SynIC
event/message pages and to enable/disable SynIC messages/events processing
in userspace.
+ /* KVM_EXIT_ARM_NISV */
+ struct {
+ __u64 esr_iss;
+ __u64 fault_ipa;
+ } arm_nisv;
+
+Used on arm and arm64 systems. If a guest accesses memory not in a memslot,
+KVM will typically return to userspace and ask it to do MMIO emulation on its
+behalf. However, for certain classes of instructions, no instruction decode
+(direction, length of memory access) is provided, and fetching and decoding
+the instruction from the VM is overly complicated to live in the kernel.
+
+Historically, when this situation occurred, KVM would print a warning and kill
+the VM. KVM assumed that if the guest accessed non-memslot memory, it was
+trying to do I/O, which just couldn't be emulated, and the warning message was
+phrased accordingly. However, what happened more often was that a guest bug
+caused access outside the guest memory areas which should lead to a more
+meaningful warning message and an external abort in the guest, if the access
+did not fall within an I/O window.
+
+Userspace implementations can query for KVM_CAP_ARM_NISV_TO_USER, and enable
+this capability at VM creation. Once this is done, these types of errors will
+instead return to userspace with KVM_EXIT_ARM_NISV, with the valid bits from
+the HSR (arm) and ESR_EL2 (arm64) in the esr_iss field, and the faulting IPA
+in the fault_ipa field. Userspace can either fix up the access if it's
+actually an I/O access by decoding the instruction from guest memory (if it's
+very brave) and continue executing the guest, or it can decide to suspend,
+dump, or restart the guest.
+
+Note that KVM does not skip the faulting instruction as it does for
+KVM_EXIT_MMIO, but userspace has to emulate any change to the processing state
+if it decides to decode and emulate the instruction.
+
/* Fix the size of the union. */
char padding[256];
};
diff --git a/Documentation/virt/kvm/arm/pvtime.rst b/Documentation/virt/kvm/arm/pvtime.rst
new file mode 100644
index 000000000000..2357dd2d8655
--- /dev/null
+++ b/Documentation/virt/kvm/arm/pvtime.rst
@@ -0,0 +1,80 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Paravirtualized time support for arm64
+======================================
+
+Arm specification DEN0057/A defines a standard for paravirtualised time
+support for AArch64 guests:
+
+https://developer.arm.com/docs/den0057/a
+
+KVM/arm64 implements the stolen time part of this specification by providing
+some hypervisor service calls to support a paravirtualized guest obtaining a
+view of the amount of time stolen from its execution.
+
+Two new SMCCC compatible hypercalls are defined:
+
+* PV_TIME_FEATURES: 0xC5000020
+* PV_TIME_ST: 0xC5000021
+
+These are only available in the SMC64/HVC64 calling convention as
+paravirtualized time is not available to 32 bit Arm guests. The existence of
+the PV_FEATURES hypercall should be probed using the SMCCC 1.1 ARCH_FEATURES
+mechanism before calling it.
+
+PV_TIME_FEATURES
+ ============= ======== ==========
+ Function ID: (uint32) 0xC5000020
+ PV_call_id: (uint32) The function to query for support.
+ Currently only PV_TIME_ST is supported.
+ Return value: (int64) NOT_SUPPORTED (-1) or SUCCESS (0) if the relevant
+ PV-time feature is supported by the hypervisor.
+ ============= ======== ==========
+
+PV_TIME_ST
+ ============= ======== ==========
+ Function ID: (uint32) 0xC5000021
+ Return value: (int64) IPA of the stolen time data structure for this
+ VCPU. On failure:
+ NOT_SUPPORTED (-1)
+ ============= ======== ==========
+
+The IPA returned by PV_TIME_ST should be mapped by the guest as normal memory
+with inner and outer write back caching attributes, in the inner shareable
+domain. A total of 16 bytes from the IPA returned are guaranteed to be
+meaningfully filled by the hypervisor (see structure below).
+
+PV_TIME_ST returns the structure for the calling VCPU.
+
+Stolen Time
+-----------
+
+The structure pointed to by the PV_TIME_ST hypercall is as follows:
+
++-------------+-------------+-------------+----------------------------+
+| Field | Byte Length | Byte Offset | Description |
++=============+=============+=============+============================+
+| Revision | 4 | 0 | Must be 0 for version 1.0 |
++-------------+-------------+-------------+----------------------------+
+| Attributes | 4 | 4 | Must be 0 |
++-------------+-------------+-------------+----------------------------+
+| Stolen time | 8 | 8 | Stolen time in unsigned |
+| | | | nanoseconds indicating how |
+| | | | much time this VCPU thread |
+| | | | was involuntarily not |
+| | | | running on a physical CPU. |
++-------------+-------------+-------------+----------------------------+
+
+All values in the structure are stored little-endian.
+
+The structure will be updated by the hypervisor prior to scheduling a VCPU. It
+will be present within a reserved region of the normal memory given to the
+guest. The guest should not attempt to write into this memory. There is a
+structure per VCPU of the guest.
+
+It is advisable that one or more 64k pages are set aside for the purpose of
+these structures and not used for other purposes, this enables the guest to map
+the region using 64k pages and avoids conflicting attributes with other memory.
+
+For the user space interface see Documentation/virt/kvm/devices/vcpu.txt
+section "3. GROUP: KVM_ARM_VCPU_PVTIME_CTRL".
diff --git a/Documentation/virt/kvm/devices/vcpu.txt b/Documentation/virt/kvm/devices/vcpu.txt
index 2b5dab16c4f2..6f3bd64a05b0 100644
--- a/Documentation/virt/kvm/devices/vcpu.txt
+++ b/Documentation/virt/kvm/devices/vcpu.txt
@@ -60,3 +60,17 @@ time to use the number provided for a given timer, overwriting any previously
configured values on other VCPUs. Userspace should configure the interrupt
numbers on at least one VCPU after creating all VCPUs and before running any
VCPUs.
+
+3. GROUP: KVM_ARM_VCPU_PVTIME_CTRL
+Architectures: ARM64
+
+3.1 ATTRIBUTE: KVM_ARM_VCPU_PVTIME_IPA
+Parameters: 64-bit base address
+Returns: -ENXIO: Stolen time not implemented
+ -EEXIST: Base address already set for this VCPU
+ -EINVAL: Base address not 64 byte aligned
+
+Specifies the base address of the stolen time structure for this VCPU. The
+base address must be 64 byte aligned and exist within a valid guest memory
+region. See Documentation/virt/kvm/arm/pvtime.txt for more information
+including the layout of the stolen time structure.
diff --git a/Documentation/virt/kvm/devices/xics.txt b/Documentation/virt/kvm/devices/xics.txt
index 42864935ac5d..423332dda7bc 100644
--- a/Documentation/virt/kvm/devices/xics.txt
+++ b/Documentation/virt/kvm/devices/xics.txt
@@ -3,9 +3,19 @@ XICS interrupt controller
Device type supported: KVM_DEV_TYPE_XICS
Groups:
- KVM_DEV_XICS_SOURCES
+ 1. KVM_DEV_XICS_GRP_SOURCES
Attributes: One per interrupt source, indexed by the source number.
+ 2. KVM_DEV_XICS_GRP_CTRL
+ Attributes:
+ 2.1 KVM_DEV_XICS_NR_SERVERS (write only)
+ The kvm_device_attr.addr points to a __u32 value which is the number of
+ interrupt server numbers (ie, highest possible vcpu id plus one).
+ Errors:
+ -EINVAL: Value greater than KVM_MAX_VCPU_ID.
+ -EFAULT: Invalid user pointer for attr->addr.
+ -EBUSY: A vcpu is already connected to the device.
+
This device emulates the XICS (eXternal Interrupt Controller
Specification) defined in PAPR. The XICS has a set of interrupt
sources, each identified by a 20-bit source number, and a set of
@@ -38,7 +48,7 @@ least-significant end of the word:
Each source has 64 bits of state that can be read and written using
the KVM_GET_DEVICE_ATTR and KVM_SET_DEVICE_ATTR ioctls, specifying the
-KVM_DEV_XICS_SOURCES attribute group, with the attribute number being
+KVM_DEV_XICS_GRP_SOURCES attribute group, with the attribute number being
the interrupt source number. The 64 bit state word has the following
bitfields, starting from the least-significant end of the word:
diff --git a/Documentation/virt/kvm/devices/xive.txt b/Documentation/virt/kvm/devices/xive.txt
index 9a24a4525253..f5d1d6b5af61 100644
--- a/Documentation/virt/kvm/devices/xive.txt
+++ b/Documentation/virt/kvm/devices/xive.txt
@@ -78,6 +78,14 @@ the legacy interrupt mode, referred as XICS (POWER7/8).
migrating the VM.
Errors: none
+ 1.3 KVM_DEV_XIVE_NR_SERVERS (write only)
+ The kvm_device_attr.addr points to a __u32 value which is the number of
+ interrupt server numbers (ie, highest possible vcpu id plus one).
+ Errors:
+ -EINVAL: Value greater than KVM_MAX_VCPU_ID.
+ -EFAULT: Invalid user pointer for attr->addr.
+ -EBUSY: A vCPU is already connected to the device.
+
2. KVM_DEV_XIVE_GRP_SOURCE (write only)
Initializes a new source in the XIVE device and mask it.
Attributes: