- 23 Sep, 2021 2 commits
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Maxim Levitsky authored
Test that if: * L1 disables virtual interrupt masking, and INTR intercept. * L1 setups a virtual interrupt to be injected to L2 and enters L2 with interrupts disabled, thus the virtual interrupt is pending. * Now an external interrupt arrives in L1 and since L1 doesn't intercept it, it should be delivered to L2 when it enables interrupts. to do this L0 (abuses) V_IRQ to setup an interrupt window, and returns to L2. * L2 enables interrupts. This should trigger the interrupt window, injection of the external interrupt and delivery of the virtual interrupt that can now be done. * Test that now L2 gets those interrupts. This is the test that demonstrates the issue that was fixed in the previous patch. Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210914154825.104886-3-mlevitsk@redhat.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Maxim Levitsky authored
In svm_clear_vintr we try to restore the virtual interrupt injection that might be pending, but we fail to restore the interrupt vector. Signed-off-by:
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- 22 Sep, 2021 37 commits
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Fares Mehanna authored
Intel PMU MSRs is in msrs_to_save_all[], so add AMD PMU MSRs to have a consistent behavior between Intel and AMD when using KVM_GET_MSRS, KVM_SET_MSRS or KVM_GET_MSR_INDEX_LIST. We have to add legacy and new MSRs to handle guests running without X86_FEATURE_PERFCTR_CORE. Signed-off-by:
Fares Mehanna <faresx@amazon.de> Message-Id: <20210915133951.22389-1-faresx@amazon.de> Signed-off-by:
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Maxim Levitsky authored
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:
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Maxim Levitsky authored
It is possible that when non root mode is entered via special entry (!from_vmentry), that is from SMM or from loading the nested state, the L2 state could be invalid in regard to non unrestricted guest mode, but later it can become valid. (for example when RSM emulation restores segment registers from SMRAM) Thus delay the check to VM entry, where we will check this and fail. Signed-off-by:
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Maxim Levitsky authored
Since no actual VM entry happened, the VM exit information is stale. To avoid this, synthesize an invalid VM guest state VM exit. Suggested-by:
Sean Christopherson <seanjc@google.com> Signed-off-by:
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Maxim Levitsky authored
Use return statements instead of nested if, and fix error path to free all the maps that were allocated. Suggested-by:
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Maxim Levitsky authored
Currently the KVM_REQ_GET_NESTED_STATE_PAGES on SVM only reloads PDPTRs, and MSR bitmap, with former not really needed for SMM as SMM exit code reloads them again from SMRAM'S CR3, and later happens to work since MSR bitmap isn't modified while in SMM. Still it is better to be consistient with VMX. Signed-off-by:
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Maxim Levitsky authored
When exiting SMM, pdpts are loaded again from the guest memory. This fixes a theoretical bug, when exit from SMM triggers entry to the nested guest which re-uses some of the migration code which uses this flag as a workaround for a legacy userspace. Signed-off-by:
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Maxim Levitsky authored
Otherwise guest entry code might see incorrect L1 state (e.g paging state). Fixes: 37be407b ("KVM: nSVM: Fix L1 state corruption upon return from SMM") Signed-off-by:
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Vitaly Kuznetsov authored
Windows Server 2022 with Hyper-V role enabled failed to boot on KVM when enlightened VMCS is advertised. Debugging revealed there are two exposed secondary controls it is not happy with: SECONDARY_EXEC_ENABLE_VMFUNC and SECONDARY_EXEC_SHADOW_VMCS. These controls are known to be unsupported, as there are no corresponding fields in eVMCSv1 (see the comment above EVMCS1_UNSUPPORTED_2NDEXEC definition). Previously, commit 31de3d25 ("x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()") introduced the required filtering mechanism for VMX MSRs but for some reason put only known to be problematic (and not full EVMCS1_UNSUPPORTED_* lists) controls there. Note, Windows Server 2022 seems to have gained some sanity check for VMX MSRs: it doesn't even try to launch a guest when there's something it doesn't like, nested_evmcs_check_controls() mechanism can't catch the problem. Let's be bold this time and instead of playing whack-a-mole just filter out all unsupported controls from VMX MSRs. Fixes: 31de3d25 ("x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()") Signed-off-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20210907163530.110066-1-vkuznets@redhat.com> Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Check for a NULL cpumask_var_t when kicking multiple vCPUs via cpumask_available(), which performs a !NULL check if and only if cpumasks are configured to be allocated off-stack. This is a meaningless optimization, e.g. avoids a TEST+Jcc and TEST+CMOV on x86, but more importantly helps document that the NULL check is necessary even though all callers pass in a local variable. No functional change intended. Cc: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by:
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Sean Christopherson authored
Fix a benign data race reported by syzbot+KCSAN[*] by ensuring vcpu->cpu is read exactly once, and by ensuring the vCPU is booted from guest mode if kvm_arch_vcpu_should_kick() returns true. Fix a similar race in kvm_make_vcpus_request_mask() by ensuring the vCPU is interrupted if kvm_request_needs_ipi() returns true. Reading vcpu->cpu before vcpu->mode (via kvm_arch_vcpu_should_kick() or kvm_request_needs_ipi()) means the target vCPU could get migrated (change vcpu->cpu) and enter !OUTSIDE_GUEST_MODE between reading vcpu->cpud and reading vcpu->mode. If that happens, the kick/IPI will be sent to the old pCPU, not the new pCPU that is now running the vCPU or reading SPTEs. Although failing to kick the vCPU is not exactly ideal, practically speaking it cannot cause a functional issue unless there is also a bug in the caller, and any such bug would exist regardless of kvm_vcpu_kick()'s behavior. The purpose of sending an IPI is purely to get a vCPU into the host (or out of reading SPTEs) so that the vCPU can recognize a change in state, e.g. a KVM_REQ_* request. If vCPU's handling of the state change is required for correctness, KVM must ensure either the vCPU sees the change before entering the guest, or that the sender sees the vCPU as running in guest mode. All architectures handle this by (a) sending the request before calling kvm_vcpu_kick() and (b) checking for requests _after_ setting vcpu->mode. x86's READING_SHADOW_PAGE_TABLES has similar requirements; KVM needs to ensure it kicks and waits for vCPUs that started reading SPTEs _before_ MMU changes were finalized, but any vCPU that starts reading after MMU changes were finalized will see the new state and can continue on uninterrupted. For uses of kvm_vcpu_kick() that are not paired with a KVM_REQ_*, e.g. x86's kvm_arch_sync_dirty_log(), the order of the kick must not be relied upon for functional correctness, e.g. in the dirty log case, userspace cannot assume it has a 100% complete log if vCPUs are still running. All that said, eliminate the benign race since the cost of doing so is an "extra" atomic cmpxchg() in the case where the target vCPU is loaded by the current pCPU or is not loaded at all. I.e. the kick will be skipped due to kvm_vcpu_exiting_guest_mode() seeing a compatible vcpu->mode as opposed to the kick being skipped because of the cpu checks. Keep the "cpu != me" checks even though they appear useless/impossible at first glance. x86 processes guest IPI writes in a fast path that runs in IN_GUEST_MODE, i.e. can call kvm_vcpu_kick() from IN_GUEST_MODE. And calling kvm_vm_bugged()->kvm_make_vcpus_request_mask() from IN_GUEST or READING_SHADOW_PAGE_TABLES is perfectly reasonable. Note, a race with the cpu_online() check in kvm_vcpu_kick() likely persists, e.g. the vCPU could exit guest mode and get offlined between the cpu_online() check and the sending of smp_send_reschedule(). But, the online check appears to exist only to avoid a WARN in x86's native_smp_send_reschedule() that fires if the target CPU is not online. The reschedule WARN exists because CPU offlining takes the CPU out of the scheduling pool, i.e. the WARN is intended to detect the case where the kernel attempts to schedule a task on an offline CPU. The actual sending of the IPI is a non-issue as at worst it will simpy be dropped on the floor. In other words, KVM's usurping of the reschedule IPI could theoretically trigger a WARN if the stars align, but there will be no loss of functionality. [*] https://syzkaller.appspot.com/bug?extid=cd4154e502f43f10808a Cc: Venkatesh Srinivas <venkateshs@google.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Fixes: 97222cc8 ("KVM: Emulate local APIC in kernel") Signed-off-by:
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Vitaly Kuznetsov authored
KASAN reports the following issue: BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm] Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798 CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G X --------- --- Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020 Call Trace: dump_stack+0xa5/0xe6 print_address_description.constprop.0+0x18/0x130 ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm] __kasan_report.cold+0x7f/0x114 ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm] kasan_report+0x38/0x50 kasan_check_range+0xf5/0x1d0 kvm_make_vcpus_request_mask+0x174/0x440 [kvm] kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm] ? kvm_arch_exit+0x110/0x110 [kvm] ? sched_clock+0x5/0x10 ioapic_write_indirect+0x59f/0x9e0 [kvm] ? static_obj+0xc0/0xc0 ? __lock_acquired+0x1d2/0x8c0 ? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm] The problem appears to be that 'vcpu_bitmap' is allocated as a single long on stack and it should really be KVM_MAX_VCPUS long. We also seem to clear the lower 16 bits of it with bitmap_zero() for no particular reason (my guess would be that 'bitmap' and 'vcpu_bitmap' variables in kvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed 16-bit long, the later should accommodate all possible vCPUs). Fixes: 7ee30bc1 ("KVM: x86: deliver KVM IOAPIC scan request to target vCPUs") Fixes: 9a2ae9f6 ("KVM: x86: Zero the IOAPIC scan request dest vCPUs bitmap") Reported-by:
Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by:
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David Matlack authored
The calculation to get the per-slot dirty bitmap was incorrect leading to a buffer overrun. Fix it by splitting out the dirty bitmap into a separate bitmap per slot. Fixes: 609e6202 ("KVM: selftests: Support multiple slots in dirty_log_perf_test") Signed-off-by:
David Matlack <dmatlack@google.com> Reviewed-by:
Andrew Jones <drjones@redhat.com> Message-Id: <20210917173657.44011-4-dmatlack@google.com> Signed-off-by:
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David Matlack authored
All selftests that support the backing_src option were printing their own description of the flag and then calling backing_src_help() to dump the list of available backing sources. Consolidate the flag printing in backing_src_help() to align indentation, reduce duplicated strings, and improve consistency across tests. Note: Passing "-s" to backing_src_help is unnecessary since every test uses the same flag. However I decided to keep it for code readability at the call sites. While here this opportunistically fixes the incorrectly interleaved printing -x help message and list of backing source types in dirty_log_perf_test. Fixes: 609e6202 ("KVM: selftests: Support multiple slots in dirty_log_perf_test") Reviewed-by:
Ben Gardon <bgardon@google.com> Reviewed-by:
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David Matlack authored
Every other KVM selftest uses -s for the backing_src, so switch demand_paging_test to match. Reviewed-by:
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Peter Gonda authored
A mirrored SEV-ES VM will need to call KVM_SEV_LAUNCH_UPDATE_VMSA to setup its vCPUs and have them measured, and their VMSAs encrypted. Without this change, it is impossible to have mirror VMs as part of SEV-ES VMs. Also allow the guest status check and debugging commands since they do not change any guest state. Signed-off-by:
Peter Gonda <pgonda@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Nathan Tempelman <natet@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Steve Rutherford <srutherford@google.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Fixes: 54526d1f ("KVM: x86: Support KVM VMs sharing SEV context", 2021-04-21) Message-Id: <20210921150345.2221634-3-pgonda@google.com> Signed-off-by:
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Peter Gonda authored
For mirroring SEV-ES the mirror VM will need more then just the ASID. The FD and the handle are required to all the mirror to call psp commands. The mirror VM will need to call KVM_SEV_LAUNCH_UPDATE_VMSA to setup its vCPUs' VMSAs for SEV-ES. Signed-off-by:
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Chenyi Qiang authored
Nested bus lock VM exits are not supported yet. If L2 triggers bus lock VM exit, it will be directed to L1 VMM, which would cause unexpected behavior. Therefore, handle L2's bus lock VM exits in L0 directly. Fixes: fe6b6bc8 ("KVM: VMX: Enable bus lock VM exit") Signed-off-by:
Chenyi Qiang <chenyi.qiang@intel.com> Reviewed-by:
Xiaoyao Li <xiaoyao.li@intel.com> Message-Id: <20210914095041.29764-1-chenyi.qiang@intel.com> Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Use vcpu_idx to identify vCPU0 when updating HyperV's TSC page, which is shared by all vCPUs and "owned" by vCPU0 (because vCPU0 is the only vCPU that's guaranteed to exist). Using kvm_get_vcpu() to find vCPU works, but it's a rather odd and suboptimal method to check the index of a given vCPU. No functional change intended. Signed-off-by:
Jim Mattson <jmattson@google.com> Reviewed-by:
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Sean Christopherson authored
Read vcpu->vcpu_idx directly instead of bouncing through the one-line wrapper, kvm_vcpu_get_idx(), and drop the wrapper. The wrapper is a remnant of the original implementation and serves no purpose; remove it before it gains more users. Back when kvm_vcpu_get_idx() was added by commit 497d72d8 ("KVM: Add kvm_vcpu_get_idx to get vcpu index in kvm->vcpus"), the implementation was more than just a simple wrapper as vcpu->vcpu_idx did not exist and retrieving the index meant walking over the vCPU array to find the given vCPU. When vcpu_idx was introduced by commit 8750e72a ("KVM: remember position in kvm->vcpus array"), the helper was left behind, likely to avoid extra thrash (but even then there were only two users, the original arm usage having been removed at some point in the past). No functional change intended. Suggested-by:
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Hou Wenlong authored
According to Intel's SDM Vol2 and AMD's APM Vol3, when CR4.TSD is set, use rdtsc/rdtscp instruction above privilege level 0 should trigger a #GP. Fixes: d7eb8203 ("KVM: SVM: Add intercept checks for remaining group7 instructions") Signed-off-by:
Hou Wenlong <houwenlong93@linux.alibaba.com> Message-Id: <1297c0dd3f1bb47a6d089f850b629c7aa0247040.1629257115.git.houwenlong93@linux.alibaba.com> Reviewed-by:
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Sean Christopherson authored
Require the target guest page to be writable when pinning memory for RECEIVE_UPDATE_DATA. Per the SEV API, the PSP writes to guest memory: The result is then encrypted with GCTX.VEK and written to the memory pointed to by GUEST_PADDR field. Fixes: 15fb7de1 ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command") Cc: stable@vger.kernel.org Cc: Peter Gonda <pgonda@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by:
Brijesh Singh <brijesh.singh@amd.com> Reviewed-by:
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Mingwei Zhang authored
DECOMMISSION the current SEV context if binding an ASID fails after RECEIVE_START. Per AMD's SEV API, RECEIVE_START generates a new guest context and thus needs to be paired with DECOMMISSION: The RECEIVE_START command is the only command other than the LAUNCH_START command that generates a new guest context and guest handle. The missing DECOMMISSION can result in subsequent SEV launch failures, as the firmware leaks memory and might not able to allocate more SEV guest contexts in the future. Note, LAUNCH_START suffered the same bug, but was previously fixed by commit 934002cd ("KVM: SVM: Call SEV Guest Decommission if ASID binding fails"). Cc: Alper Gun <alpergun@google.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: David Rienjes <rientjes@google.com> Cc: Marc Orr <marcorr@google.com> Cc: John Allen <john.allen@amd.com> Cc: Peter Gonda <pgonda@google.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vipin Sharma <vipinsh@google.com> Cc: stable@vger.kernel.org Reviewed-by:Marc Orr <marcorr@google.com> Acked-by:
Mingwei Zhang <mizhang@google.com> Reviewed-by:
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Peter Gonda authored
The update-VMSA ioctl touches data stored in struct kvm_vcpu, and therefore should not be performed concurrently with any VCPU ioctl that might cause KVM or the processor to use the same data. Adds vcpu mutex guard to the VMSA updating code. Refactors out __sev_launch_update_vmsa() function to deal with per vCPU parts of sev_launch_update_vmsa(). Fixes: ad73109a ("KVM: SVM: Provide support to launch and run an SEV-ES guest") Signed-off-by:
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Sergey Senozhatsky authored
grow_halt_poll_ns() ignores values between 0 and halt_poll_ns_grow_start (10000 by default). However, when we shrink halt_poll_ns we may fall way below halt_poll_ns_grow_start and endup with halt_poll_ns values that don't make a lot of sense: like 1 or 9, or 19. VCPU1 trace (halt_poll_ns_shrink equals 2): VCPU1 grow 10000 VCPU1 shrink 5000 VCPU1 shrink 2500 VCPU1 shrink 1250 VCPU1 shrink 625 VCPU1 shrink 312 VCPU1 shrink 156 VCPU1 shrink 78 VCPU1 shrink 39 VCPU1 shrink 19 VCPU1 shrink 9 VCPU1 shrink 4 Mirror what grow_halt_poll_ns() does and set halt_poll_ns to 0 as soon as new shrink-ed halt_poll_ns value falls below halt_poll_ns_grow_start. Signed-off-by:
Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by:
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Yu Zhang authored
"VMXON pointer" is saved in vmx->nested.vmxon_ptr since commit 3573e22c ("KVM: nVMX: additional checks on vmxon region"). Also, handle_vmptrld() & handle_vmclear() now have logic to check the VMCS pointer against the VMXON pointer. So just remove the obsolete comments of handle_vmon(). Signed-off-by:
Yu Zhang <yu.c.zhang@linux.intel.com> Message-Id: <20210908171731.18885-1-yu.c.zhang@linux.intel.com> Signed-off-by:
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Haimin Zhang authored
Check the return of init_srcu_struct(), which can fail due to OOM, when initializing the page track mechanism. Lack of checking leads to a NULL pointer deref found by a modified syzkaller. Reported-by:
TCS Robot <tcs_robot@tencent.com> Signed-off-by:
Haimin Zhang <tcs_kernel@tencent.com> Message-Id: <1630636626-12262-1-git-send-email-tcs_kernel@tencent.com> [Move the call towards the beginning of kvm_arch_init_vm. - Paolo] Signed-off-by:
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Sean Christopherson authored
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: ee9d22e0 ("KVM: VMX: Use flag to indicate "active" uret MSRs instead of sorting list") Signed-off-by:
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Oliver Upton authored
The SMC64 calling convention passes a function identifier in w0 and its parameters in x1-x17. Given this, there are two deviations in the SMC64 call performed by the steal_time test: the function identifier is assigned to a 64 bit register and the parameter is only 32 bits wide. Align the call with the SMCCC by using a 32 bit register to handle the function identifier and increasing the parameter width to 64 bits. Suggested-by:
Oliver Upton <oupton@google.com> Reviewed-by:
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Oliver Upton authored
The logical not operator applies only to the left hand side of a bitwise operator. As such, the check for POLLIN not being set in revents wrong. Fix it by adding parentheses around the bitwise expression. Fixes: 4f72180e ("KVM: selftests: Add demand paging content to the demand paging test") Reviewed-by:
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Sean Christopherson authored
Explicitly zero the guest's CR3 and mark it available+dirty at RESET/INIT. Per Intel's SDM and AMD's APM, CR3 is zeroed at both RESET and INIT. For RESET, this is a nop as vcpu is zero-allocated. For INIT, the bug has likely escaped notice because no firmware/kernel puts its page tables root at PA=0, let alone relies on INIT to get the desired CR3 for such page tables. Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Mark all registers as available and dirty at vCPU creation, as the vCPU has obviously not been loaded into hardware, let alone been given the chance to be modified in hardware. On SVM, reading from "uninitialized" hardware is a non-issue as VMCBs are zero allocated (thus not truly uninitialized) and hardware does not allow for arbitrary field encoding schemes. On VMX, backing memory for VMCSes is also zero allocated, but true initialization of the VMCS _technically_ requires VMWRITEs, as the VMX architectural specification technically allows CPU implementations to encode fields with arbitrary schemes. E.g. a CPU could theoretically store the inverted value of every field, which would result in VMREAD to a zero-allocated field returns all ones. In practice, only the AR_BYTES fields are known to be manipulated by hardware during VMREAD/VMREAD; no known hardware or VMM (for nested VMX) does fancy encoding of cacheable field values (CR0, CR3, CR4, etc...). In other words, this is technically a bug fix, but practically speakings it's a glorified nop. Failure to mark registers as available has been a lurking bug for quite some time. The original register caching supported only GPRs (+RIP, which is kinda sorta a GPR), with the masks initialized at ->vcpu_reset(). That worked because the two cacheable registers, RIP and RSP, are generally speaking not read as side effects in other flows. Arguably, commit aff48baa ("KVM: Fetch guest cr3 from hardware on demand") was the first instance of failure to mark regs available. While _just_ marking CR3 available during vCPU creation wouldn't have fixed the VMREAD from an uninitialized VMCS bug because ept_update_paging_mode_cr0() unconditionally read vmcs.GUEST_CR3, marking CR3 _and_ intentionally not reading GUEST_CR3 when it's available would have avoided VMREAD to a technically-uninitialized VMCS. Fixes: aff48baa ("KVM: Fetch guest cr3 from hardware on demand") Fixes: 6de4f3ad ("KVM: Cache pdptrs") Fixes: 6de12732 ("KVM: VMX: Optimize vmx_get_rflags()") Fixes: 2fb92db1 ("KVM: VMX: Cache vmcs segment fields") Fixes: bd31fe49 ("KVM: VMX: Add proper cache tracking for CR0") Fixes: f98c1e77 ("KVM: VMX: Add proper cache tracking for CR4") Fixes: 5addc235 ("KVM: VMX: Cache vmcs.EXIT_QUALIFICATION using arch avail_reg flags") Fixes: 87915858 ("KVM: VMX: Cache vmcs.EXIT_INTR_INFO using arch avail_reg flags") Signed-off-by:
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Sean Christopherson authored
Revert the __NR_userfaultfd syscall fallback added for KVM selftests now that x86's unistd_{32,63}.h overrides are under uapi/ and thus not in KVM selftests' search path, i.e. now that KVM gets x86 syscall numbers from the installed kernel headers. No functional change intended. Reviewed-by: -
Sean Christopherson authored
Add a test to verify an rseq's CPU ID is updated correctly if the task is migrated while the kernel is handling KVM_RUN. This is a regression test for a bug introduced by commit 72c3c0fe ("x86/kvm: Use generic xfer to guest work function"), where TIF_NOTIFY_RESUME would be cleared by KVM without updating rseq, leading to a stale CPU ID and other badness. Signed-off-by:
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Message-Id: <20210901203030.1292304-5-seanjc@google.com> Signed-off-by:
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Sean Christopherson authored
Move unistd_{32,64}.h from x86/include/asm to x86/include/uapi/asm so that tools/selftests that install kernel headers, e.g. KVM selftests, can include non-uapi tools headers, e.g. to get 'struct list_head', without effectively overriding the installed non-tool uapi headers. Swapping KVM's search order, e.g. to search the kernel headers before tool headers, is not a viable option as doing results in linux/type.h and other core headers getting pulled from the kernel headers, which do not have the kernel-internal typedefs that are used through tools, including many files outside of selftests/kvm's control. Prior to commit cec07f53 ("perf tools: Move syscall number fallbacks from perf-sys.h to tools/arch/x86/include/asm/"), the handcoded numbers were actual fallbacks, i.e. overriding unistd_{32,64}.h from the kernel headers was unintentional. Signed-off-by: -
Sean Christopherson authored
Invoke rseq_handle_notify_resume() from tracehook_notify_resume() now that the two function are always called back-to-back by architectures that have rseq. The rseq helper is stubbed out for architectures that don't support rseq, i.e. this is a nop across the board. Note, tracehook_notify_resume() is horribly named and arguably does not belong in tracehook.h as literally every line of code in it has nothing to do with tracing. But, that's been true since commit a42c6ded ("move key_repace_session_keyring() into tracehook_notify_resume()") first usurped tracehook_notify_resume() back in 2012. Punt cleaning that mess up to future patches. No functional change intended. Acked-by:
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Sean Christopherson authored
Invoke rseq's NOTIFY_RESUME handler when processing the flag prior to transferring to a KVM guest, which is roughly equivalent to an exit to userspace and processes many of the same pending actions. While the task cannot be in an rseq critical section as the KVM path is reachable only by via ioctl(KVM_RUN), the side effects that apply to rseq outside of a critical section still apply, e.g. the current CPU needs to be updated if the task is migrated. Clearing TIF_NOTIFY_RESUME without informing rseq can lead to segfaults and other badness in userspace VMMs that use rseq in combination with KVM, e.g. due to the CPU ID being stale after task migration. Fixes: 72c3c0fe ("x86/kvm: Use generic xfer to guest work function") Reported-by:
Peter Foley <pefoley@google.com> Bisected-by:
Doug Evans <dje@google.com> Acked-by:
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- 20 Sep, 2021 1 commit
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Linus Torvalds authored
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