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2022-02-25Revert "KVM: VMX: Save HOST_CR3 in vmx_set_host_fs_gs()"Sean Christopherson1-3/+2
Undo a nested VMX fix as a step toward reverting the commit it fixed, 15ad9762d69f ("KVM: VMX: Save HOST_CR3 in vmx_prepare_switch_to_guest()"), as the underlying premise that "host CR3 in the vcpu thread can only be changed when scheduling" is wrong. This reverts commit a9f2705ec84449e3b8d70c804766f8e97e23080d. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220224191917.3508476-2-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 Christopherson1-0/+3
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>
2022-01-14kvm: x86: Disable interception for IA32_XFD on demandKevin Tian1-1/+1
Always intercepting IA32_XFD causes non-negligible overhead when this register is updated frequently in the guest. Disable r/w emulation after intercepting the first WRMSR(IA32_XFD) with a non-zero value. Disable WRMSR emulation implies that IA32_XFD becomes out-of-sync with the software states in fpstate and the per-cpu xfd cache. This leads to two additional changes accordingly: - Call fpu_sync_guest_vmexit_xfd_state() after vm-exit to bring software states back in-sync with the MSR, before handle_exit_irqoff() is called. - Always trap #NM once write interception is disabled for IA32_XFD. The #NM exception is rare if the guest doesn't use dynamic features. Otherwise, there is at most one exception per guest task given a dynamic feature. p.s. We have confirmed that SDM is being revised to say that when setting IA32_XFD[18] the AMX register state is not guaranteed to be preserved. This clarification avoids adding mess for a creative guest which sets IA32_XFD[18]=1 before saving active AMX state to its own storage. Signed-off-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Jing Liu <jing2.liu@intel.com> Signed-off-by: Yang Zhong <yang.zhong@intel.com> Message-Id: <20220105123532.12586-22-yang.zhong@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-14kvm: x86: Disable RDMSR interception of IA32_XFD_ERRJing Liu1-1/+1
This saves one unnecessary VM-exit in guest #NM handler, given that the MSR is already restored with the guest value before the guest is resumed. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jing Liu <jing2.liu@intel.com> Signed-off-by: Yang Zhong <yang.zhong@intel.com> Message-Id: <20220105123532.12586-15-yang.zhong@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-07KVM: VMX: Save HOST_CR3 in vmx_set_host_fs_gs()Lai Jiangshan1-2/+3
The host CR3 in the vcpu thread can only be changed when scheduling, so commit 15ad9762d69f ("KVM: VMX: Save HOST_CR3 in vmx_prepare_switch_to_guest()") changed vmx.c to only save it in vmx_prepare_switch_to_guest(). However, it also has to be synced in vmx_sync_vmcs_host_state() when switching VMCS. vmx_set_host_fs_gs() is called in both places, so rename it to vmx_set_vmcs_host_state() and make it update HOST_CR3. Fixes: 15ad9762d69f ("KVM: VMX: Save HOST_CR3 in vmx_prepare_switch_to_guest()") Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> Message-Id: <20211216021938.11752-2-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-08KVM: nVMX: Track whether changes in L0 require MSR bitmap for L2 to be rebuiltVitaly Kuznetsov1-0/+9
Introduce a flag to keep track of whether MSR bitmap for L2 needs to be rebuilt due to changes in MSR bitmap for L1 or switching to a different L2. This information will be used for Enlightened MSR Bitmap feature for Hyper-V guests. Note, setting msr_bitmap_changed to 'true' from set_current_vmptr() is not really needed for Enlightened MSR Bitmap as the feature can only be used in conjunction with Enlightened VMCS but let's keep tracking information complete, it's cheap and in the future similar PV feature can easily be implemented for KVM on KVM too. No functional change intended. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211129094704.326635-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-08KVM: vmx, svm: clean up mass updates to regs_avail/regs_dirty bitsPaolo Bonzini1-13/+15
Document the meaning of the three combinations of regs_avail and regs_dirty. Update regs_dirty just after writeback instead of doing it later after vmexit. After vmexit, instead, we clear the regs_avail bits corresponding to lazily-loaded registers. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-18KVM: nVMX: Use a gfn_to_hva_cache for vmptrldDavid Woodhouse1-0/+5
And thus another call to kvm_vcpu_map() can die. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20211115165030.7422-7-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-18KVM: nVMX: Use kvm_{read,write}_guest_cached() for shadow_vmcs12David Woodhouse1-0/+5
Using kvm_vcpu_map() for reading from the guest is entirely gratuitous, when all we do is a single memcpy and unmap it again. Fix it up to use kvm_read_guest()... but in fact I couldn't bring myself to do that without also making it use a gfn_to_hva_cache for both that *and* the copy in the other direction. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20211115165030.7422-5-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-11KVM: VMX: Add a helper function to retrieve the GPR index for INVPCID, ↵Vipin Sharma1-0/+5
INVVPID, and INVEPT handle_invept(), handle_invvpid(), handle_invpcid() read the same reg2 field in vmcs.VMX_INSTRUCTION_INFO to get the index of the GPR that holds the invalidation type. Add a helper to retrieve reg2 from VMX instruction info to consolidate and document the shift+mask magic. Signed-off-by: Vipin Sharma <vipinsh@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109174426.2350547-2-vipinsh@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-11KVM: VMX: Macrofy the MSR bitmap getters and settersSean Christopherson1-60/+25
Add builder macros to generate the MSR bitmap helpers to reduce the amount of copy-paste code, especially with respect to all the magic numbers needed to calc the correct bit location. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109013047.2041518-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-11KVM: nVMX: Handle dynamic MSR intercept togglingSean Christopherson1-0/+63
Always check vmcs01's MSR bitmap when merging L0 and L1 bitmaps for L2, and always update the relevant bits in vmcs02. This fixes two distinct, but intertwined bugs related to dynamic MSR bitmap modifications. The first issue is that KVM fails to enable MSR interception in vmcs02 for the FS/GS base MSRs if L1 first runs L2 with interception disabled, and later enables interception. The second issue is that KVM fails to honor userspace MSR filtering when preparing vmcs02. Fix both issues simultaneous as fixing only one of the issues (doesn't matter which) would create a mess that no one should have to bisect. Fixing only the first bug would exacerbate the MSR filtering issue as userspace would see inconsistent behavior depending on the whims of L1. Fixing only the second bug (MSR filtering) effectively requires fixing the first, as the nVMX code only knows how to transition vmcs02's bitmap from 1->0. Move the various accessor/mutators that are currently buried in vmx.c into vmx.h so that they can be shared by the nested code. Fixes: 1a155254ff93 ("KVM: x86: Introduce MSR filtering") Fixes: d69129b4e46a ("KVM: nVMX: Disable intercept for FS/GS base MSRs in vmcs02 when possible") Cc: stable@vger.kernel.org Cc: Alexander Graf <graf@amazon.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109013047.2041518-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-10-22KVM: VMX: Rename pt_desc.addr_range to pt_desc.num_address_rangesXiaoyao Li1-1/+1
To better self explain the meaning of this field and match the PT_CAP_num_address_ranges constatn. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> Message-Id: <20210827070249.924633-4-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: x86: nVMX: re-evaluate emulation_required on nested VM exitMaxim Levitsky1-0/+1
If L1 had invalid state on VM entry (can happen on SMM transactions when we enter from real mode, straight to nested guest), then after we load 'host' state from VMCS12, the state has to become valid again, but since we load the segment registers with __vmx_set_segment we weren't always updating emulation_required. Update emulation_required explicitly at end of load_vmcs12_host_state. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210913140954.165665-8-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: VMX: Remove defunct "nr_active_uret_msrs" fieldSean Christopherson1-4/+0
Remove vcpu_vmx.nr_active_uret_msrs and its associated comment, which are both defunct now that KVM keeps the list constant and instead explicitly tracks which entries need to be loaded into hardware. No functional change intended. Fixes: ee9d22e08d13 ("KVM: VMX: Use flag to indicate "active" uret MSRs instead of sorting list") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210908002401.1947049-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-13KVM: VMX: Hide VMCS control calculators in vmx.cSean Christopherson1-26/+0
Now that nested VMX pulls KVM's desired VMCS controls from vmcs01 instead of re-calculating on the fly, bury the helpers that do the calcluations in vmx.c. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210810171952.2758100-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-13KVM: VMX: Drop caching of KVM's desired sec exec controls for vmcs01Sean Christopherson1-2/+1
Remove the secondary execution controls cache now that it's effectively dead code; it is only read immediately after it is written. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210810171952.2758100-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-13KVM: nVMX: Pull KVM L0's desired controls directly from vmcs01Sean Christopherson1-1/+5
When preparing controls for vmcs02, grab KVM's desired controls from vmcs01's shadow state instead of recalculating the controls from scratch, or in the secondary execution controls, instead of using the dedicated cache. Calculating secondary exec controls is eye-poppingly expensive due to the guest CPUID checks, hence the dedicated cache, but the other calculations aren't exactly free either. Explicitly clear several bits (x2APIC, DESC exiting, and load EFER on exit) as appropriate as they may be set in vmcs01, whereas the previous implementation relied on dynamic bits being cleared in the calculator. Intentionally propagate VM_{ENTRY,EXIT}_LOAD_IA32_PERF_GLOBAL_CTRL from vmcs01 to vmcs02. Whether or not PERF_GLOBAL_CTRL is loaded depends on whether or not perf itself is active, so unless perf stops between the exit from L1 and entry to L2, vmcs01 will hold the desired value. This is purely an optimization as atomic_switch_perf_msrs() will set/clear the control as needed at VM-Enter, i.e. it avoids two extra VMWRITEs in the case where perf is active (versus starting with the bits clear in vmcs02, which was the previous behavior). Cc: Zeng Guang <guang.zeng@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210810171952.2758100-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-10Merge branch 'kvm-vmx-secctl' into HEADPaolo Bonzini1-1/+1
Merge common topic branch for 5.14-rc6 and 5.15 merge window.
2021-08-10KVM: VMX: Use current VMCS to query WAITPKG support for MSR emulationSean Christopherson1-1/+1
Use the secondary_exec_controls_get() accessor in vmx_has_waitpkg() to effectively get the controls for the current VMCS, as opposed to using vmx->secondary_exec_controls, which is the cached value of KVM's desired controls for vmcs01 and truly not reflective of any particular VMCS. While the waitpkg control is not dynamic, i.e. vmcs01 will always hold the same waitpkg configuration as vmx->secondary_exec_controls, the same does not hold true for vmcs02 if the L1 VMM hides the feature from L2. If L1 hides the feature _and_ does not intercept MSR_IA32_UMWAIT_CONTROL, L2 could incorrectly read/write L1's virtual MSR instead of taking a #GP. Fixes: 6e3ba4abcea5 ("KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210810171952.2758100-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-02KVM: VMX: Smush x2APIC MSR bitmap adjustments into single functionSean Christopherson1-1/+1
Consolidate all of the dynamic MSR bitmap adjustments into vmx_update_msr_bitmap_x2apic(), and rename the mode tracker to reflect that it is x2APIC specific. If KVM gains more cases of dynamic MSR pass-through, odds are very good that those new cases will be better off with their own logic, e.g. see Intel PT MSRs and MSR_IA32_SPEC_CTRL. Attempting to handle all updates in a common helper did more harm than good, as KVM ended up collecting a large number of useless "updates". Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210713163324.627647-42-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-02KVM: nVMX: Remove obsolete MSR bitmap refresh at nested transitionsSean Christopherson1-1/+0
Drop unnecessary MSR bitmap updates during nested transitions, as L1's APIC_BASE MSR is not modified by the standard VM-Enter/VM-Exit flows, and L2's MSR bitmap is managed separately. In the unlikely event that L1 is pathological and loads APIC_BASE via the VM-Exit load list, KVM will handle updating the bitmap in its normal WRMSR flows. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210713163324.627647-39-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-02KVM: nVMX: Don't evaluate "emulation required" on nested VM-ExitSean Christopherson1-1/+1
Use the "internal" variants of setting segment registers when stuffing state on nested VM-Exit in order to skip the "emulation required" updates. VM-Exit must always go to protected mode, and all segments are mostly hardcoded (to valid values) on VM-Exit. The bits of the segments that aren't hardcoded are explicitly checked during VM-Enter, e.g. the selector RPLs must all be zero. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210713163324.627647-30-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-07-15KVM: VMX: Remove vmx_msr_index from vmx.hYu Zhang1-2/+0
vmx_msr_index was used to record the list of MSRs which can be lazily restored when kvm returns to userspace. It is now reimplemented as kvm_uret_msrs_list, a common x86 list which is only used inside x86.c. So just remove the obsolete declaration in vmx.h. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Message-Id: <20210707235702.31595-1-yu.c.zhang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-24KVM: nVMX: Handle split-lock #AC exceptions that happen in L2Sean Christopherson1-0/+1
Mark #ACs that won't be reinjected to the guest as wanted by L0 so that KVM handles split-lock #AC from L2 instead of forwarding the exception to L1. Split-lock #AC isn't yet virtualized, i.e. L1 will treat it like a regular #AC and do the wrong thing, e.g. reinject it into L2. Fixes: e6f8b6c12f03 ("KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guest") Cc: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210622172244.3561540-1-seanjc@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17KVM: x86: hyper-v: Move the remote TLB flush logic out of vmxVineeth Pillai1-9/+0
Currently the remote TLB flush logic is specific to VMX. Move it to a common place so that SVM can use it as well. Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com> Message-Id: <4f4e4ca19778437dae502f44363a38e99e3ef5d1.1622730232.git.viremana@linux.microsoft.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17KVM: X86: Add vendor callbacks for writing the TSC multiplierIlias Stamatis1-8/+0
Currently vmx_vcpu_load_vmcs() writes the TSC_MULTIPLIER field of the VMCS every time the VMCS is loaded. Instead of doing this, set this field from common code on initialization and whenever the scaling ratio changes. Additionally remove vmx->current_tsc_ratio. This field is redundant as vcpu->arch.tsc_scaling_ratio already tracks the current TSC scaling ratio. The vmx->current_tsc_ratio field is only used for avoiding unnecessary writes but it is no longer needed after removing the code from the VMCS load path. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Ilias Stamatis <ilstam@amazon.com> Message-Id: <20210607105438.16541-1-ilstam@amazon.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17KVM: X86: Add functions for retrieving L2 TSC fields from common codeIlias Stamatis1-0/+3
In order to implement as much of the nested TSC scaling logic as possible in common code, we need these vendor callbacks for retrieving the TSC offset and the TSC multiplier that L1 has set for L2. Signed-off-by: Ilias Stamatis <ilstam@amazon.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210526184418.28881-7-ilstam@amazon.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-07KVM: VMX: Use flag to indicate "active" uret MSRs instead of sorting listSean Christopherson1-1/+1
Explicitly flag a uret MSR as needing to be loaded into hardware instead of resorting the list of "active" MSRs and tracking how many MSRs in total need to be loaded. The only benefit to sorting the list is that the loop to load MSRs during vmx_prepare_switch_to_guest() doesn't need to iterate over all supported uret MRS, only those that are active. But that is a pointless optimization, as the most common case, running a 64-bit guest, will load the vast majority of MSRs. Not to mention that a single WRMSR is far more expensive than iterating over the list. Providing a stable list order obviates the need to track a given MSR's "slot" in the per-CPU list of user return MSRs; all lists simply use the same ordering. Future patches will take advantage of the stable order to further simplify the related code. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210504171734.1434054-10-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-07KVM: VMX: Configure list of user return MSRs at module initSean Christopherson1-1/+9
Configure the list of user return MSRs that are actually supported at module init instead of reprobing the list of possible MSRs every time a vCPU is created. Curating the list on a per-vCPU basis is pointless; KVM is completely hosed if the set of supported MSRs changes after module init, or if the set of MSRs differs per physical PCU. The per-vCPU lists also increase complexity (see __vmx_find_uret_msr()) and creates corner cases that _should_ be impossible, but theoretically exist in KVM, e.g. advertising RDTSCP to userspace without actually being able to virtualize RDTSCP if probing MSR_TSC_AUX fails. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210504171734.1434054-9-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-26KVM: VMX: Invert the inlining of MSR interception helpersSean Christopherson1-2/+13
Invert the inline declarations of the MSR interception helpers between the wrapper, vmx_set_intercept_for_msr(), and the core implementations, vmx_{dis,en}able_intercept_for_msr(). Letting the compiler _not_ inline the implementation reduces KVM's code footprint by ~3k bytes. Back when the helpers were added in commit 904e14fb7cb9 ("KVM: VMX: make MSR bitmaps per-VCPU"), both the wrapper and the implementations were __always_inline because the end code distilled down to a few conditionals and a bit operation. Today, the implementations involve a variety of checks and bit ops in order to support userspace MSR filtering. Furthermore, the vast majority of calls to manipulate MSR interception are not performance sensitive, e.g. vCPU creation and x2APIC toggling. On the other hand, the one path that is performance sensitive, dynamic LBR passthrough, uses the wrappers, i.e. is largely untouched by inverting the inlining. In short, forcing the low level MSR interception code to be inlined no longer makes sense. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210423221912.3857243-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20KVM: VMX: Add emulation of SGX Launch Control LE hash MSRsSean Christopherson1-0/+3
Emulate the four Launch Enclave public key hash MSRs (LE hash MSRs) that exist on CPUs that support SGX Launch Control (LC). SGX LC modifies the behavior of ENCLS[EINIT] to use the LE hash MSRs when verifying the key used to sign an enclave. On CPUs without LC support, the LE hash is hardwired into the CPU to an Intel controlled key (the Intel key is also the reset value of the LE hash MSRs). Track the guest's desired hash so that a future patch can stuff the hash into the hardware MSRs when executing EINIT on behalf of the guest, when those MSRs are writable in host. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Co-developed-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Message-Id: <c58ef601ddf88f3a113add837969533099b1364a.1618196135.git.kai.huang@intel.com> [Add a comment regarding the MSRs being available until SGX is locked. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-17KVM: x86: dump_vmcs should show the effective EFERDavid Edmondson1-1/+1
If EFER is not being loaded from the VMCS, show the effective value by reference to the MSR autoload list or calculation. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Edmondson <david.edmondson@oracle.com> Message-Id: <20210318120841.133123-5-david.edmondson@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-15KVM: VMX: Track root HPA instead of EPTP for paravirt Hyper-V TLB flushSean Christopherson1-3/+3
Track the address of the top-level EPT struct, a.k.a. the root HPA, instead of the EPTP itself for Hyper-V's paravirt TLB flush. The paravirt API takes only the address, not the full EPTP, and in theory tracking the EPTP could lead to false negatives, e.g. if the HPA matched but the attributes in the EPTP do not. In practice, such a mismatch is extremely unlikely, if not flat out impossible, given how KVM generates the EPTP. Opportunsitically rename the related fields to use the 'root' nomenclature, and to prefix them with 'hv_' to connect them to Hyper-V's paravirt TLB flushing. Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210305183123.3978098-12-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-15KVM: VMX: Define Hyper-V paravirt TLB flush fields iff Hyper-V is enabledSean Christopherson1-0/+4
Ifdef away the Hyper-V specific fields in structs kvm_vmx and vcpu_vmx as each field has only a single reference outside of the struct itself that isn't already wrapped in ifdeffery (and both are initialization). vcpu_vmx.ept_pointer in particular should be wrapped as it is valid if and only if Hyper-v is active, i.e. non-Hyper-V code cannot rely on it to actually track the current EPTP (without additional code changes). Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210305183123.3978098-10-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-15KVM: VMX: Invalidate hv_tlb_eptp to denote an EPTP mismatchSean Christopherson1-7/+0
Drop the dedicated 'ept_pointers_match' field in favor of stuffing 'hv_tlb_eptp' with INVALID_PAGE to mark it as invalid, i.e. to denote that there is at least one EPTP mismatch. Use a local variable to track whether or not a mismatch is detected so that hv_tlb_eptp can be used to skip redundant flushes. No functional change intended. Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210305183123.3978098-7-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-15KVM: VMX: Track common EPTP for Hyper-V's paravirt TLB flushSean Christopherson1-0/+1
Explicitly track the EPTP that is common to all vCPUs instead of grabbing vCPU0's EPTP when invoking Hyper-V's paravirt TLB flush. Tracking the EPTP will allow optimizing the checks when loading a new EPTP and will also allow dropping ept_pointer_match, e.g. by marking the common EPTP as invalid. This also technically fixes a bug where KVM could theoretically flush an invalid GPA if all vCPUs have an invalid root. In practice, it's likely impossible to trigger a remote TLB flush in such a scenario. In any case, the superfluous flush is completely benign. Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210305183123.3978098-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-15KVM: x86: Get active PCID only when writing a CR3 valueSean Christopherson1-2/+1
Retrieve the active PCID only when writing a guest CR3 value, i.e. don't get the PCID when using EPT or NPT. The PCID is especially problematic for EPT as the bits have different meaning, and so the PCID and must be manually stripped, which is annoying and unnecessary. And on VMX, getting the active PCID also involves reading the guest's CR3 and CR4.PCIDE, i.e. may add pointless VMREADs. Opportunistically rename the pgd/pgd_level params to root_hpa and root_level to better reflect their new roles. Keep the function names, as "load the guest PGD" is still accurate/correct. Last, and probably least, pass root_hpa as a hpa_t/u64 instead of an unsigned long. The EPTP holds a 64-bit value, even in 32-bit mode, so in theory EPT could support HIGHMEM for 32-bit KVM. Never mind that doing so would require changing the MMU page allocators and reworking the MMU to use kmap(). Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210305183123.3978098-2-seanjc@google.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-19KVM: VMX: Dynamically enable/disable PML based on memslot dirty loggingMakarand Sonare1-0/+2
Currently, if enable_pml=1 PML remains enabled for the entire lifetime of the VM irrespective of whether dirty logging is enable or disabled. When dirty logging is disabled, all the pages of the VM are manually marked dirty, so that PML is effectively non-operational. Setting the dirty bits is an expensive operation which can cause severe MMU lock contention in a performance sensitive path when dirty logging is disabled after a failed or canceled live migration. Manually setting dirty bits also fails to prevent PML activity if some code path clears dirty bits, which can incur unnecessary VM-Exits. In order to avoid this extra overhead, dynamically enable/disable PML when dirty logging gets turned on/off for the first/last memslot. Signed-off-by: Makarand Sonare <makarandsonare@google.com> Co-developed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210213005015.1651772-12-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM/nVMX: Use __vmx_vcpu_run in nested_vmx_check_vmentry_hwUros Bizjak1-0/+1
Replace inline assembly in nested_vmx_check_vmentry_hw with a call to __vmx_vcpu_run. The function is not performance critical, so (double) GPR save/restore in __vmx_vcpu_run can be tolerated, as far as performance effects are concerned. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Reviewed-and-tested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> [sean: dropped versioning info from changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20201231002702.2223707-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: X86: prepend vmx/svm prefix to additional kvm_x86_ops functionsJason Baron1-1/+1
A subsequent patch introduces macros in preparation for simplifying the definition for vmx_x86_ops and svm_x86_ops. Making the naming more uniform expands the coverage of the macros. Add vmx/svm prefix to the following functions: update_exception_bitmap(), enable_nmi_window(), enable_irq_window(), update_cr8_intercept and enable_smi_window(). Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Jason Baron <jbaron@akamai.com> Message-Id: <ed594696f8e2c2b2bfc747504cee9bbb2a269300.1610680941.git.jbaron@akamai.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: vmx/pmu: Reduce the overhead of LBR pass-through or cancellationLike Xu1-0/+3
When the LBR records msrs has already been pass-through, there is no need to call vmx_update_intercept_for_lbr_msrs() again and again, and vice versa. Signed-off-by: Like Xu <like.xu@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Message-Id: <20210201051039.255478-8-like.xu@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: vmx/pmu: Pass-through LBR msrs when the guest LBR event is ACTIVELike Xu1-0/+1
In addition to DEBUGCTLMSR_LBR, any KVM trap caused by LBR msrs access will result in a creation of guest LBR event per-vcpu. If the guest LBR event is scheduled on with the corresponding vcpu context, KVM will pass-through all LBR records msrs to the guest. The LBR callstack mechanism implemented in the host could help save/restore the guest LBR records during the event context switches, which reduces a lot of overhead if we save/restore tens of LBR msrs (e.g. 32 LBR records entries) in the much more frequent VMX transitions. To avoid reclaiming LBR resources from any higher priority event on host, KVM would always check the exist of guest LBR event and its state before vm-entry as late as possible. A negative result would cancel the pass-through state, and it also prevents real registers accesses and potential data leakage. If host reclaims the LBR between two checks, the interception state and LBR records can be safely preserved due to native save/restore support from guest LBR event. The KVM emits a pr_warn() when the LBR hardware is unavailable to the guest LBR event. The administer is supposed to reminder users that the guest result may be inaccurate if someone is using LBR to record hypervisor on the host side. Suggested-by: Andi Kleen <ak@linux.intel.com> Co-developed-by: Wei Wang <wei.w.wang@intel.com> Signed-off-by: Wei Wang <wei.w.wang@intel.com> Signed-off-by: Like Xu <like.xu@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Message-Id: <20210201051039.255478-7-like.xu@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: vmx/pmu: Create a guest LBR event when vcpu sets DEBUGCTLMSR_LBRLike Xu1-0/+10
When vcpu sets DEBUGCTLMSR_LBR in the MSR_IA32_DEBUGCTLMSR, the KVM handler would create a guest LBR event which enables the callstack mode and none of hardware counter is assigned. The host perf would schedule and enable this event as usual but in an exclusive way. The guest LBR event will be released when the vPMU is reset but soon, the lazy release mechanism would be applied to this event like a vPMC. Suggested-by: Andi Kleen <ak@linux.intel.com> Co-developed-by: Wei Wang <wei.w.wang@intel.com> Signed-off-by: Wei Wang <wei.w.wang@intel.com> Signed-off-by: Like Xu <like.xu@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Message-Id: <20210201051039.255478-6-like.xu@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: vmx/pmu: Add PMU_CAP_LBR_FMT check when guest LBR is enabledLike Xu1-0/+1
Usespace could set the bits [0, 5] of the IA32_PERF_CAPABILITIES MSR which tells about the record format stored in the LBR records. The LBR will be enabled on the guest if host perf supports LBR (checked via x86_perf_get_lbr()) and the vcpu model is compatible with the host one. Signed-off-by: Like Xu <like.xu@linux.intel.com> Message-Id: <20210201051039.255478-4-like.xu@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: vmx/pmu: Add PMU_CAP_LBR_FMT check when guest LBR is enabledPaolo Bonzini1-0/+11
Usespace could set the bits [0, 5] of the IA32_PERF_CAPABILITIES MSR which tells about the record format stored in the LBR records. The LBR will be enabled on the guest if host perf supports LBR (checked via x86_perf_get_lbr()) and the vcpu model is compatible with the host one. Signed-off-by: Like Xu <like.xu@linux.intel.com> Message-Id: <20210201051039.255478-4-like.xu@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: x86/vmx: Make vmx_set_intercept_for_msr() non-staticLike Xu1-0/+2
To make code responsibilities clear, we may resue and invoke the vmx_set_intercept_for_msr() in other vmx-specific files (e.g. pmu_intel.c), so expose it to passthrough LBR msrs later. Signed-off-by: Like Xu <like.xu@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Message-Id: <20210201051039.255478-2-like.xu@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: VMX: Enable bus lock VM exitChenyi Qiang1-1/+1
Virtual Machine can exploit bus locks to degrade the performance of system. Bus lock can be caused by split locked access to writeback(WB) memory or by using locks on uncacheable(UC) memory. The bus lock is typically >1000 cycles slower than an atomic operation within a cache line. It also disrupts performance on other cores (which must wait for the bus lock to be released before their memory operations can complete). To address the threat, bus lock VM exit is introduced to notify the VMM when a bus lock was acquired, allowing it to enforce throttling or other policy based mitigations. A VMM can enable VM exit due to bus locks by setting a new "Bus Lock Detection" VM-execution control(bit 30 of Secondary Processor-based VM execution controls). If delivery of this VM exit was preempted by a higher priority VM exit (e.g. EPT misconfiguration, EPT violation, APIC access VM exit, APIC write VM exit, exception bitmap exiting), bit 26 of exit reason in vmcs field is set to 1. In current implementation, the KVM exposes this capability through KVM_CAP_X86_BUS_LOCK_EXIT. The user can get the supported mode bitmap (i.e. off and exit) and enable it explicitly (disabled by default). If bus locks in guest are detected by KVM, exit to user space even when current exit reason is handled by KVM internally. Set a new field KVM_RUN_BUS_LOCK in vcpu->run->flags to inform the user space that there is a bus lock detected in guest. Document for Bus Lock VM exit is now available at the latest "Intel Architecture Instruction Set Extensions Programming Reference". Document Link: https://software.intel.com/content/www/us/en/develop/download/intel-architecture-instruction-set-extensions-programming-reference.html Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com> Message-Id: <20201106090315.18606-4-chenyi.qiang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: VMX: Convert vcpu_vmx.exit_reason to a unionSean Christopherson1-1/+24
Convert vcpu_vmx.exit_reason from a u32 to a union (of size u32). The full VM_EXIT_REASON field is comprised of a 16-bit basic exit reason in bits 15:0, and single-bit modifiers in bits 31:16. Historically, KVM has only had to worry about handling the "failed VM-Entry" modifier, which could only be set in very specific flows and required dedicated handling. I.e. manually stripping the FAILED_VMENTRY bit was a somewhat viable approach. But even with only a single bit to worry about, KVM has had several bugs related to comparing a basic exit reason against the full exit reason store in vcpu_vmx. Upcoming Intel features, e.g. SGX, will add new modifier bits that can be set on more or less any VM-Exit, as opposed to the significantly more restricted FAILED_VMENTRY, i.e. correctly handling everything in one-off flows isn't scalable. Tracking exit reason in a union forces code to explicitly choose between consuming the full exit reason and the basic exit, and is a convenient way to document and access the modifiers. No functional change intended. Cc: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com> Message-Id: <20201106090315.18606-2-chenyi.qiang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-11-15KVM: x86: Move vendor CR4 validity check to dedicated kvm_x86_ops hookSean Christopherson1-1/+1
Split out VMX's checks on CR4.VMXE to a dedicated hook, .is_valid_cr4(), and invoke the new hook from kvm_valid_cr4(). This fixes an issue where KVM_SET_SREGS would return success while failing to actually set CR4. Fixing the issue by explicitly checking kvm_x86_ops.set_cr4()'s return in __set_sregs() is not a viable option as KVM has already stuffed a variety of vCPU state. Note, kvm_valid_cr4() and is_valid_cr4() have different return types and inverted semantics. This will be remedied in a future patch. Fixes: 5e1746d6205d ("KVM: nVMX: Allow setting the VMXE bit in CR4") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20201007014417.29276-5-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-27 18:27:55 +0300