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2022-06-16KVM: x86/speculation: Disable Fill buffer clear within guestsPawan Gupta2-1/+77
commit 027bbb884be006b05d9c577d6401686053aa789e upstream The enumeration of MD_CLEAR in CPUID(EAX=7,ECX=0).EDX{bit 10} is not an accurate indicator on all CPUs of whether the VERW instruction will overwrite fill buffers. FB_CLEAR enumeration in IA32_ARCH_CAPABILITIES{bit 17} covers the case of CPUs that are not vulnerable to MDS/TAA, indicating that microcode does overwrite fill buffers. Guests running in VMM environments may not be aware of all the capabilities/vulnerabilities of the host CPU. Specifically, a guest may apply MDS/TAA mitigations when a virtual CPU is enumerated as vulnerable to MDS/TAA even when the physical CPU is not. On CPUs that enumerate FB_CLEAR_CTRL the VMM may set FB_CLEAR_DIS to skip overwriting of fill buffers by the VERW instruction. This is done by setting FB_CLEAR_DIS during VMENTER and resetting on VMEXIT. For guests that enumerate FB_CLEAR (explicitly asking for fill buffer clear capability) the VMM will not use FB_CLEAR_DIS. Irrespective of guest state, host overwrites CPU buffers before VMENTER to protect itself from an MMIO capable guest, as part of mitigation for MMIO Stale Data vulnerabilities. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [cascardo: arch/x86/kvm/vmx.c has been split and context adjustment at vmx_vcpu_run] [cascardo: moved functions so they are after struct vcpu_vmx definition] [cascardo: fb_clear is disabled/enabled around __vmx_vcpu_run] [cascardo: conflict context fixups] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-16x86/speculation/mmio: Add mitigation for Processor MMIO Stale DataPawan Gupta1-0/+3
commit 8cb861e9e3c9a55099ad3d08e1a3b653d29c33ca upstream Processor MMIO Stale Data is a class of vulnerabilities that may expose data after an MMIO operation. For details please refer to Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst. These vulnerabilities are broadly categorized as: Device Register Partial Write (DRPW): Some endpoint MMIO registers incorrectly handle writes that are smaller than the register size. Instead of aborting the write or only copying the correct subset of bytes (for example, 2 bytes for a 2-byte write), more bytes than specified by the write transaction may be written to the register. On some processors, this may expose stale data from the fill buffers of the core that created the write transaction. Shared Buffers Data Sampling (SBDS): After propagators may have moved data around the uncore and copied stale data into client core fill buffers, processors affected by MFBDS can leak data from the fill buffer. Shared Buffers Data Read (SBDR): It is similar to Shared Buffer Data Sampling (SBDS) except that the data is directly read into the architectural software-visible state. An attacker can use these vulnerabilities to extract data from CPU fill buffers using MDS and TAA methods. Mitigate it by clearing the CPU fill buffers using the VERW instruction before returning to a user or a guest. On CPUs not affected by MDS and TAA, user application cannot sample data from CPU fill buffers using MDS or TAA. A guest with MMIO access can still use DRPW or SBDR to extract data architecturally. Mitigate it with VERW instruction to clear fill buffers before VMENTER for MMIO capable guests. Add a kernel parameter mmio_stale_data={off|full|full,nosmt} to control the mitigation. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [cascardo: arch/x86/kvm/vmx.c has been moved] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-12kvm: x86/cpuid: Only provide CPUID leaf 0xA if host has architectural PMUSandipan Das1-0/+5
[ Upstream commit 5a1bde46f98b893cda6122b00e94c0c40a6ead3c ] On some x86 processors, CPUID leaf 0xA provides information on Architectural Performance Monitoring features. It advertises a PMU version which Qemu uses to determine the availability of additional MSRs to manage the PMCs. Upon receiving a KVM_GET_SUPPORTED_CPUID ioctl request for the same, the kernel constructs return values based on the x86_pmu_capability irrespective of the vendor. This leaf and the additional MSRs are not supported on AMD and Hygon processors. If AMD PerfMonV2 is detected, the PMU version is set to 2 and guest startup breaks because of an attempt to access a non-existent MSR. Return zeros to avoid this. Fixes: a6c06ed1a60a ("KVM: Expose the architectural performance monitoring CPUID leaf") Reported-by: Vasant Hegde <vasant.hegde@amd.com> Signed-off-by: Sandipan Das <sandipan.das@amd.com> Message-Id: <3fef83d9c2b2f7516e8ff50d60851f29a4bcb716.1651058600.git.sandipan.das@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20KVM: x86/svm: Clear reserved bits written to PerfEvtSeln MSRsJim Mattson1-5/+3
[ Upstream commit 9b026073db2f1ad0e4d8b61c83316c8497981037 ] AMD EPYC CPUs never raise a #GP for a WRMSR to a PerfEvtSeln MSR. Some reserved bits are cleared, and some are not. Specifically, on Zen3/Milan, bits 19 and 42 are not cleared. When emulating such a WRMSR, KVM should not synthesize a #GP, regardless of which bits are set. However, undocumented bits should not be passed through to the hardware MSR. So, rather than checking for reserved bits and synthesizing a #GP, just clear the reserved bits. This may seem pedantic, but since KVM currently does not support the "Host/Guest Only" bits (41:40), it is necessary to clear these bits rather than synthesizing #GP, because some popular guests (e.g Linux) will set the "Host Only" bit even on CPUs that don't support EFER.SVME, and they don't expect a #GP. For example, root@Ubuntu1804:~# perf stat -e r26 -a sleep 1 Performance counter stats for 'system wide': 0 r26 1.001070977 seconds time elapsed Feb 23 03:59:58 Ubuntu1804 kernel: [ 405.379957] unchecked MSR access error: WRMSR to 0xc0010200 (tried to write 0x0000020000130026) at rIP: 0xffffffff9b276a28 (native_write_msr+0x8/0x30) Feb 23 03:59:58 Ubuntu1804 kernel: [ 405.379958] Call Trace: Feb 23 03:59:58 Ubuntu1804 kernel: [ 405.379963] amd_pmu_disable_event+0x27/0x90 Fixes: ca724305a2b0 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM") Reported-by: Lotus Fenn <lotusf@google.com> Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Like Xu <likexu@tencent.com> Reviewed-by: David Dunn <daviddunn@google.com> Message-Id: <20220226234131.2167175-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20KVM: x86: Forbid VMM to set SYNIC/STIMER MSRs when SynIC wasn't activatedVitaly Kuznetsov1-0/+15
commit b1e34d325397a33d97d845e312d7cf2a8b646b44 upstream. Setting non-zero values to SYNIC/STIMER MSRs activates certain features, this should not happen when KVM_CAP_HYPERV_SYNIC{,2} was not activated. Note, it would've been better to forbid writing anything to SYNIC/STIMER MSRs, including zeroes, however, at least QEMU tries clearing HV_X64_MSR_STIMER0_CONFIG without SynIC. HV_X64_MSR_EOM MSR is somewhat 'special' as writing zero there triggers an action, this also should not happen when SynIC wasn't activated. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220325132140.25650-4-vkuznets@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-20KVM: x86/emulator: Defer not-present segment check in ↵Hou Wenlong1-5/+9
__load_segment_descriptor() [ Upstream commit ca85f002258fdac3762c57d12d5e6e401b6a41af ] Per Intel's SDM on the "Instruction Set Reference", when loading segment descriptor, not-present segment check should be after all type and privilege checks. But the emulator checks it first, then #NP is triggered instead of #GP if privilege fails and segment is not present. Put not-present segment check after type and privilege checks in __load_segment_descriptor(). Fixes: 38ba30ba51a00 (KVM: x86 emulator: Emulate task switch in emulator.c) Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> Message-Id: <52573c01d369f506cadcf7233812427cf7db81a7.1644292363.git.houwenlong.hwl@antgroup.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20KVM: x86: Fix emulation in writing cr8Zhenzhong Duan1-4/+1
[ Upstream commit f66af9f222f08d5b11ea41c1bd6c07a0f12daa07 ] In emulation of writing to cr8, one of the lowest four bits in TPR[3:0] is kept. According to Intel SDM 10.8.6.1(baremetal scenario): "APIC.TPR[bits 7:4] = CR8[bits 3:0], APIC.TPR[bits 3:0] = 0"; and SDM 28.3(use TPR shadow): "MOV to CR8. The instruction stores bits 3:0 of its source operand into bits 7:4 of VTPR; the remainder of VTPR (bits 3:0 and bits 31:8) are cleared."; and AMD's APM 16.6.4: "Task Priority Sub-class (TPS)-Bits 3 : 0. The TPS field indicates the current sub-priority to be used when arbitrating lowest-priority messages. This field is written with zero when TPR is written using the architectural CR8 register."; so in KVM emulated scenario, clear TPR[3:0] to make a consistent behavior as in other scenarios. This doesn't impact evaluation and delivery of pending virtual interrupts because processor does not use the processor-priority sub-class to determine which interrupts to delivery and which to inhibit. Sub-class is used by hardware to arbitrate lowest priority interrupts, but KVM just does a round-robin style delivery. Fixes: b93463aa59d6 ("KVM: Accelerated apic support") Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220210094506.20181-1-zhenzhong.duan@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-23KVM: x86/pmu: Use AMD64_RAW_EVENT_MASK for PERF_TYPE_RAWJim Mattson1-1/+1
[ Upstream commit 710c476514313c74045c41c0571bb5178fd16e3d ] AMD's event select is 3 nybbles, with the high nybble in bits 35:32 of a PerfEvtSeln MSR. Don't mask off the high nybble when configuring a RAW perf event. Fixes: ca724305a2b0 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM") Signed-off-by: Jim Mattson <jmattson@google.com> Message-Id: <20220203014813.2130559-2-jmattson@google.com> Reviewed-by: David Dunn <daviddunn@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-12Revert "x86/kvm: fix vcpu-id indexed array sizes"Juergen Gross2-3/+3
commit 1e254d0d86a0f2efd4190a89d5204b37c18c6381 upstream. This reverts commit 76b4f357d0e7d8f6f0013c733e6cba1773c266d3. The commit has the wrong reasoning, as KVM_MAX_VCPU_ID is not defining the maximum allowed vcpu-id as its name suggests, but the number of vcpu-ids. So revert this patch again. Suggested-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20210913135745.13944-2-jgross@suse.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-22KVM: x86: Update vCPU's hv_clock before back to guest when tsc_offset is ↵Zelin Deng1-0/+4
adjusted commit d9130a2dfdd4b21736c91b818f87dbc0ccd1e757 upstream. When MSR_IA32_TSC_ADJUST is written by guest due to TSC ADJUST feature especially there's a big tsc warp (like a new vCPU is hot-added into VM which has been up for a long time), tsc_offset is added by a large value then go back to guest. This causes system time jump as tsc_timestamp is not adjusted in the meantime and pvclock monotonic character. To fix this, just notify kvm to update vCPU's guest time before back to guest. Cc: stable@vger.kernel.org Signed-off-by: Zelin Deng <zelin.deng@linux.alibaba.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1619576521-81399-2-git-send-email-zelin.deng@linux.alibaba.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-03KVM: X86: MMU: Use the correct inherited permissions to get shadow pageLai Jiangshan1-5/+9
commit b1bd5cba3306691c771d558e94baa73e8b0b96b7 upstream. When computing the access permissions of a shadow page, use the effective permissions of the walk up to that point, i.e. the logic AND of its parents' permissions. Two guest PxE entries that point at the same table gfn need to be shadowed with different shadow pages if their parents' permissions are different. KVM currently uses the effective permissions of the last non-leaf entry for all non-leaf entries. Because all non-leaf SPTEs have full ("uwx") permissions, and the effective permissions are recorded only in role.access and merged into the leaves, this can lead to incorrect reuse of a shadow page and eventually to a missing guest protection page fault. For example, here is a shared pagetable: pgd[] pud[] pmd[] virtual address pointers /->pmd1(u--)->pte1(uw-)->page1 <- ptr1 (u--) /->pud1(uw-)--->pmd2(uw-)->pte2(uw-)->page2 <- ptr2 (uw-) pgd-| (shared pmd[] as above) \->pud2(u--)--->pmd1(u--)->pte1(uw-)->page1 <- ptr3 (u--) \->pmd2(uw-)->pte2(uw-)->page2 <- ptr4 (u--) pud1 and pud2 point to the same pmd table, so: - ptr1 and ptr3 points to the same page. - ptr2 and ptr4 points to the same page. (pud1 and pud2 here are pud entries, while pmd1 and pmd2 here are pmd entries) - First, the guest reads from ptr1 first and KVM prepares a shadow page table with role.access=u--, from ptr1's pud1 and ptr1's pmd1. "u--" comes from the effective permissions of pgd, pud1 and pmd1, which are stored in pt->access. "u--" is used also to get the pagetable for pud1, instead of "uw-". - Then the guest writes to ptr2 and KVM reuses pud1 which is present. The hypervisor set up a shadow page for ptr2 with pt->access is "uw-" even though the pud1 pmd (because of the incorrect argument to kvm_mmu_get_page in the previous step) has role.access="u--". - Then the guest reads from ptr3. The hypervisor reuses pud1's shadow pmd for pud2, because both use "u--" for their permissions. Thus, the shadow pmd already includes entries for both pmd1 and pmd2. - At last, the guest writes to ptr4. This causes no vmexit or pagefault, because pud1's shadow page structures included an "uw-" page even though its role.access was "u--". Any kind of shared pagetable might have the similar problem when in virtual machine without TDP enabled if the permissions are different from different ancestors. In order to fix the problem, we change pt->access to be an array, and any access in it will not include permissions ANDed from child ptes. The test code is: https://lore.kernel.org/kvm/20210603050537.19605-1-jiangshanlai@gmail.com/ Remember to test it with TDP disabled. The problem had existed long before the commit 41074d07c78b ("KVM: MMU: Fix inherited permissions for emulated guest pte updates"), and it is hard to find which is the culprit. So there is no fixes tag here. Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> Message-Id: <20210603052455.21023-1-jiangshanlai@gmail.com> Cc: stable@vger.kernel.org Fixes: cea0f0e7ea54 ("[PATCH] KVM: MMU: Shadow page table caching") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [OP: - apply arch/x86/kvm/mmu/* changes to arch/x86/kvm - apply documentation changes to Documentation/virtual/kvm/mmu.txt - add vcpu parameter to gpte_access() call] Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-03KVM: x86/mmu: Treat NX as used (not reserved) for all !TDP shadow MMUsSean Christopherson1-1/+10
commit 112022bdb5bc372e00e6e43cb88ee38ea67b97bd upstream Mark NX as being used for all non-nested shadow MMUs, as KVM will set the NX bit for huge SPTEs if the iTLB mutli-hit mitigation is enabled. Checking the mitigation itself is not sufficient as it can be toggled on at any time and KVM doesn't reset MMU contexts when that happens. KVM could reset the contexts, but that would require purging all SPTEs in all MMUs, for no real benefit. And, KVM already forces EFER.NX=1 when TDP is disabled (for WP=0, SMEP=1, NX=0), so technically NX is never reserved for shadow MMUs. Fixes: b8e8c8303ff2 ("kvm: mmu: ITLB_MULTIHIT mitigation") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [sudip: use old path and adjust context] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-26KVM: nSVM: avoid picking up unsupported bits from L2 in int_ctl (CVE-2021-3653)Maxim Levitsky1-7/+8
[ upstream commit 0f923e07124df069ba68d8bb12324398f4b6b709 ] * Invert the mask of bits that we pick from L2 in nested_vmcb02_prepare_control * Invert and explicitly use VIRQ related bits bitmask in svm_clear_vintr This fixes a security issue that allowed a malicious L1 to run L2 with AVIC enabled, which allowed the L2 to exploit the uninitialized and enabled AVIC to read/write the host physical memory at some offsets. Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler") Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-26KVM: nSVM: always intercept VMLOAD/VMSAVE when nested (CVE-2021-3656)Maxim Levitsky1-0/+3
[ upstream commit c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc ] If L1 disables VMLOAD/VMSAVE intercepts, and doesn't enable Virtual VMLOAD/VMSAVE (currently not supported for the nested hypervisor), then VMLOAD/VMSAVE must operate on the L1 physical memory, which is only possible by making L0 intercept these instructions. Failure to do so allowed the nested guest to run VMLOAD/VMSAVE unintercepted, and thus read/write portions of the host physical memory. Fixes: 89c8a4984fc9 ("KVM: SVM: Enable Virtual VMLOAD VMSAVE feature") Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-04x86/kvm: fix vcpu-id indexed array sizesJuergen Gross2-3/+3
commit 76b4f357d0e7d8f6f0013c733e6cba1773c266d3 upstream. KVM_MAX_VCPU_ID is the maximum vcpu-id of a guest, and not the number of vcpu-ids. Fix array indexed by vcpu-id to have KVM_MAX_VCPU_ID+1 elements. Note that this is currently no real problem, as KVM_MAX_VCPU_ID is an odd number, resulting in always enough padding being available at the end of those arrays. Nevertheless this should be fixed in order to avoid rare problems in case someone is using an even number for KVM_MAX_VCPU_ID. Signed-off-by: Juergen Gross <jgross@suse.com> Message-Id: <20210701154105.23215-2-jgross@suse.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-04KVM: x86: determine if an exception has an error code only when injecting it.Maxim Levitsky1-4/+9
commit b97f074583736c42fb36f2da1164e28c73758912 upstream. A page fault can be queued while vCPU is in real paged mode on AMD, and AMD manual asks the user to always intercept it (otherwise result is undefined). The resulting VM exit, does have an error code. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210225154135.405125-2-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Zubin Mithra <zsm@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-20KVM: X86: Disable hardware breakpoints unconditionally before kvm_x86->run()Lai Jiangshan1-0/+2
commit f85d40160691881a17a397c448d799dfc90987ba upstream. When the host is using debug registers but the guest is not using them nor is the guest in guest-debug state, the kvm code does not reset the host debug registers before kvm_x86->run(). Rather, it relies on the hardware vmentry instruction to automatically reset the dr7 registers which ensures that the host breakpoints do not affect the guest. This however violates the non-instrumentable nature around VM entry and exit; for example, when a host breakpoint is set on vcpu->arch.cr2, Another issue is consistency. When the guest debug registers are active, the host breakpoints are reset before kvm_x86->run(). But when the guest debug registers are inactive, the host breakpoints are delayed to be disabled. The host tracing tools may see different results depending on what the guest is doing. To fix the problems, we clear %db7 unconditionally before kvm_x86->run() if the host has set any breakpoints, no matter if the guest is using them or not. Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> Message-Id: <20210628172632.81029-1-jiangshanlai@gmail.com> Cc: stable@vger.kernel.org [Only clear %db7 instead of reloading all debug registers. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-20KVM: x86: Use guest MAXPHYADDR from CPUID.0x8000_0008 iff TDP is enabledSean Christopherson1-1/+7
commit 4bf48e3c0aafd32b960d341c4925b48f416f14a5 upstream. Ignore the guest MAXPHYADDR reported by CPUID.0x8000_0008 if TDP, i.e. NPT, is disabled, and instead use the host's MAXPHYADDR. Per AMD'S APM: Maximum guest physical address size in bits. This number applies only to guests using nested paging. When this field is zero, refer to the PhysAddrSize field for the maximum guest physical address size. Fixes: 24c82e576b78 ("KVM: Sanitize cpuid") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210623230552.4027702-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-10KVM: SVM: Truncate GPR value for DR and CR accesses in !64-bit modeSean Christopherson1-4/+4
commit 0884335a2e653b8a045083aa1d57ce74269ac81d upstream. Drop bits 63:32 on loads/stores to/from DRs and CRs when the vCPU is not in 64-bit mode. The APM states bits 63:32 are dropped for both DRs and CRs: In 64-bit mode, the operand size is fixed at 64 bits without the need for a REX prefix. In non-64-bit mode, the operand size is fixed at 32 bits and the upper 32 bits of the destination are forced to 0. Fixes: 7ff76d58a9dc ("KVM: SVM: enhance MOV CR intercept handler") Fixes: cae3797a4639 ("KVM: SVM: enhance mov DR intercept handler") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210422022128.3464144-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [sudip: manual backport to old file] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-22KVM: x86: Cancel pvclock_gtod_work on module removalThomas Gleixner1-0/+1
commit 594b27e677b35f9734b1969d175ebc6146741109 upstream. Nothing prevents the following: pvclock_gtod_notify() queue_work(system_long_wq, &pvclock_gtod_work); ... remove_module(kvm); ... work_queue_run() pvclock_gtod_work() <- UAF Ditto for any other operation on that workqueue list head which touches pvclock_gtod_work after module removal. Cancel the work in kvm_arch_exit() to prevent that. Fixes: 16e8d74d2da9 ("KVM: x86: notifier for clocksource changes") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Message-Id: <87czu4onry.ffs@nanos.tec.linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-04KVM: x86: get smi pending status correctlyJay Zhou1-0/+5
commit 1f7becf1b7e21794fc9d460765fe09679bc9b9e0 upstream. The injection process of smi has two steps: Qemu KVM Step1: cpu->interrupt_request &= \ ~CPU_INTERRUPT_SMI; kvm_vcpu_ioctl(cpu, KVM_SMI) call kvm_vcpu_ioctl_smi() and kvm_make_request(KVM_REQ_SMI, vcpu); Step2: kvm_vcpu_ioctl(cpu, KVM_RUN, 0) call process_smi() if kvm_check_request(KVM_REQ_SMI, vcpu) is true, mark vcpu->arch.smi_pending = true; The vcpu->arch.smi_pending will be set true in step2, unfortunately if vcpu paused between step1 and step2, the kvm_run->immediate_exit will be set and vcpu has to exit to Qemu immediately during step2 before mark vcpu->arch.smi_pending true. During VM migration, Qemu will get the smi pending status from KVM using KVM_GET_VCPU_EVENTS ioctl at the downtime, then the smi pending status will be lost. Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com> Signed-off-by: Shengen Zhuang <zhuangshengen@huawei.com> Message-Id: <20210118084720.1585-1-jianjay.zhou@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-04KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in intel_arch_events[]Like Xu1-1/+1
commit 98dd2f108e448988d91e296173e773b06fb978b8 upstream. The HW_REF_CPU_CYCLES event on the fixed counter 2 is pseudo-encoded as 0x0300 in the intel_perfmon_event_map[]. Correct its usage. Fixes: 62079d8a4312 ("KVM: PMU: add proper support for fixed counter 2") Signed-off-by: Like Xu <like.xu@linux.intel.com> Message-Id: <20201230081916.63417-1-like.xu@linux.intel.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-12KVM: x86: fix shift out of bounds reported by UBSANPaolo Bonzini1-1/+1
commit 2f80d502d627f30257ba7e3655e71c373b7d1a5a upstream. Since we know that e >= s, we can reassociate the left shift, changing the shifted number from 1 to 2 in exchange for decreasing the right hand side by 1. Reported-by: syzbot+e87846c48bf72bc85311@syzkaller.appspotmail.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-22KVM: x86: clflushopt should be treated as a no-op by emulationDavid Edmondson1-1/+7
commit 51b958e5aeb1e18c00332e0b37c5d4e95a3eff84 upstream. The instruction emulator ignores clflush instructions, yet fails to support clflushopt. Treat both similarly. Fixes: 13e457e0eebf ("KVM: x86: Emulator does not decode clflush well") Signed-off-by: David Edmondson <david.edmondson@oracle.com> Message-Id: <20201103120400.240882-1-david.edmondson@oracle.com> Reviewed-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-29KVM: x86: emulating RDPID failure shall return #UD rather than #GPRobert Hoo1-1/+1
[ Upstream commit a9e2e0ae686094571378c72d8146b5a1a92d0652 ] Per Intel's SDM, RDPID takes a #UD if it is unsupported, which is more or less what KVM is emulating when MSR_TSC_AUX is not available. In fact, there are no scenarios in which RDPID is supposed to #GP. Fixes: fb6d4d340e ("KVM: x86: emulate RDPID") Signed-off-by: Robert Hoo <robert.hu@linux.intel.com> Message-Id: <1598581422-76264-1-git-send-email-robert.hu@linux.intel.com> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29KVM: SVM: Initialize prev_ga_tag before useSuravee Suthikulpanit1-0/+1
commit f6426ab9c957e97418ac5b0466538792767b1738 upstream. The function amd_ir_set_vcpu_affinity makes use of the parameter struct amd_iommu_pi_data.prev_ga_tag to determine if it should delete struct amd_iommu_pi_data from a list when not running in AVIC mode. However, prev_ga_tag is initialized only when AVIC is enabled. The non-zero uninitialized value can cause unintended code path, which ends up making use of the struct vcpu_svm.ir_list and ir_list_lock without being initialized (since they are intended only for the AVIC case). This triggers NULL pointer dereference bug in the function vm_ir_list_del with the following call trace: svm_update_pi_irte+0x3c2/0x550 [kvm_amd] ? proc_create_single_data+0x41/0x50 kvm_arch_irq_bypass_add_producer+0x40/0x60 [kvm] __connect+0x5f/0xb0 [irqbypass] irq_bypass_register_producer+0xf8/0x120 [irqbypass] vfio_msi_set_vector_signal+0x1de/0x2d0 [vfio_pci] vfio_msi_set_block+0x77/0xe0 [vfio_pci] vfio_pci_set_msi_trigger+0x25c/0x2f0 [vfio_pci] vfio_pci_set_irqs_ioctl+0x88/0xb0 [vfio_pci] vfio_pci_ioctl+0x2ea/0xed0 [vfio_pci] ? alloc_file_pseudo+0xa5/0x100 vfio_device_fops_unl_ioctl+0x26/0x30 [vfio] ? vfio_device_fops_unl_ioctl+0x26/0x30 [vfio] __x64_sys_ioctl+0x96/0xd0 do_syscall_64+0x37/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Therefore, initialize prev_ga_tag to zero before use. This should be safe because ga_tag value 0 is invalid (see function avic_vm_init). Fixes: dfa20099e26e ("KVM: SVM: Refactor AVIC vcpu initialization into avic_init_vcpu()") Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20201003232707.4662-1-suravee.suthikulpanit@amd.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-29KVM: x86/mmu: Commit zap of remaining invalid pages when recovering lpagesSean Christopherson1-0/+1
commit e89505698c9f70125651060547da4ff5046124fc upstream. Call kvm_mmu_commit_zap_page() after exiting the "prepare zap" loop in kvm_recover_nx_lpages() to finish zapping pages in the unlikely event that the loop exited due to lpage_disallowed_mmu_pages being empty. Because the recovery thread drops mmu_lock() when rescheduling, it's possible that lpage_disallowed_mmu_pages could be emptied by a different thread without to_zap reaching zero despite to_zap being derived from the number of disallowed lpages. Fixes: 1aa9b9572b105 ("kvm: x86: mmu: Recovery of shattered NX large pages") Cc: Junaid Shahid <junaids@google.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200923183735.584-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-01KVM: Remove CREATE_IRQCHIP/SET_PIT2 raceSteve Rutherford1-2/+8
[ Upstream commit 7289fdb5dcdbc5155b5531529c44105868a762f2 ] Fixes a NULL pointer dereference, caused by the PIT firing an interrupt before the interrupt table has been initialized. SET_PIT2 can race with the creation of the IRQchip. In particular, if SET_PIT2 is called with a low PIT timer period (after the creation of the IOAPIC, but before the instantiation of the irq routes), the PIT can fire an interrupt at an uninitialized table. Signed-off-by: Steve Rutherford <srutherford@google.com> Signed-off-by: Jon Cargille <jcargill@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Message-Id: <20200416191152.259434-1-jcargill@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01KVM: x86: fix incorrect comparison in trace eventPaolo Bonzini1-1/+1
[ Upstream commit 147f1a1fe5d7e6b01b8df4d0cbd6f9eaf6b6c73b ] The "u" field in the event has three states, -1/0/1. Using u8 however means that comparison with -1 will always fail, so change to signed char. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-23KVM: VMX: Don't freeze guest when event delivery causes an APIC-access exitWanpeng Li1-0/+1
commit 99b82a1437cb31340dbb2c437a2923b9814a7b15 upstream. According to SDM 27.2.4, Event delivery causes an APIC-access VM exit. Don't report internal error and freeze guest when event delivery causes an APIC-access exit, it is handleable and the event will be re-injected during the next vmentry. Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Message-Id: <1597827327-25055-2-git-send-email-wanpengli@tencent.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-05KVM: LAPIC: Prevent setting the tscdeadline timer if the lapic is hw disabledWanpeng Li1-1/+1
commit d2286ba7d574ba3103a421a2f9ec17cb5b0d87a1 upstream. Prevent setting the tscdeadline timer if the lapic is hw disabled. Fixes: bce87cce88 (KVM: x86: consolidate different ways to test for in-kernel LAPIC) Cc: <stable@vger.kernel.org> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Message-Id: <1596165141-28874-1-git-send-email-wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-05x86/kvm: Be careful not to clear KVM_VCPU_FLUSH_TLB bitSasha Levin1-0/+3
[ Upstream commit 8c6de56a42e0c657955e12b882a81ef07d1d073e ] kvm_steal_time_set_preempted() may accidentally clear KVM_VCPU_FLUSH_TLB bit if it is called more than once while VCPU is preempted. This is part of CVE-2019-3016. (This bug was also independently discovered by Jim Mattson <jmattson@google.com>) Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Joao Martins <joao.m.martins@oracle.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-22KVM: x86: Mark CR4.TSD as being possibly owned by the guestSean Christopherson2-1/+3
commit 7c83d096aed055a7763a03384f92115363448b71 upstream. Mark CR4.TSD as being possibly owned by the guest as that is indeed the case on VMX. Without TSD being tagged as possibly owned by the guest, a targeted read of CR4 to get TSD could observe a stale value. This bug is benign in the current code base as the sole consumer of TSD is the emulator (for RDTSC) and the emulator always "reads" the entirety of CR4 when grabbing bits. Add a build-time assertion in to ensure VMX doesn't hand over more CR4 bits without also updating x86. Fixes: 52ce3c21aec3 ("x86,kvm,vmx: Don't trap writes to CR4.TSD") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200703040422.31536-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-22KVM: x86: Inject #GP if guest attempts to toggle CR4.LA57 in 64-bit modeSean Christopherson1-0/+2
commit d74fcfc1f0ff4b6c26ecef1f9e48d8089ab4eaac upstream. Inject a #GP on MOV CR4 if CR4.LA57 is toggled in 64-bit mode, which is illegal per Intel's SDM: CR4.LA57 57-bit linear addresses (bit 12 of CR4) ... blah blah blah ... This bit cannot be modified in IA-32e mode. Note, the pseudocode for MOV CR doesn't call out the fault condition, which is likely why the check was missed during initial development. This is arguably an SDM bug and will hopefully be fixed in future release of the SDM. Fixes: fd8cb433734ee ("KVM: MMU: Expose the LA57 feature to VM.") Cc: stable@vger.kernel.org Reported-by: Sebastien Boeuf <sebastien.boeuf@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200703021714.5549-1-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-22KVM: x86: bit 8 of non-leaf PDPEs is not reservedPaolo Bonzini1-1/+1
commit 5ecad245de2ae23dc4e2dbece92f8ccfbaed2fa7 upstream. Bit 8 would be the "global" bit, which does not quite make sense for non-leaf page table entries. Intel ignores it; AMD ignores it in PDEs and PDPEs, but reserves it in PML4Es. Probably, earlier versions of the AMD manual documented it as reserved in PDPEs as well, and that behavior made it into KVM as well as kvm-unit-tests; fix it. Cc: stable@vger.kernel.org Reported-by: Nadav Amit <namit@vmware.com> Fixes: a0c0feb57992 ("KVM: x86: reserve bit 8 of non-leaf PDPEs and PML4Es in 64-bit mode on AMD", 2014-09-03) Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-30KVM: nVMX: Plumb L2 GPA through to PML emulationSean Christopherson4-9/+9
commit 2dbebf7ae1ed9a420d954305e2c9d5ed39ec57c3 upstream. Explicitly pass the L2 GPA to kvm_arch_write_log_dirty(), which for all intents and purposes is vmx_write_pml_buffer(), instead of having the latter pull the GPA from vmcs.GUEST_PHYSICAL_ADDRESS. If the dirty bit update is the result of KVM emulation (rare for L2), then the GPA in the VMCS may be stale and/or hold a completely unrelated GPA. Fixes: c5f983f6e8455 ("nVMX: Implement emulated Page Modification Logging") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200622215832.22090-2-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-30KVM: X86: Fix MSR range of APIC registers in X2APIC modeXiaoyao Li1-2/+2
commit bf10bd0be53282183f374af23577b18b5fbf7801 upstream. Only MSR address range 0x800 through 0x8ff is architecturally reserved and dedicated for accessing APIC registers in x2APIC mode. Fixes: 0105d1a52640 ("KVM: x2apic interface to lapic") Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> Message-Id: <20200616073307.16440-1-xiaoyao.li@intel.com> Cc: stable@vger.kernel.org Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-25KVM: x86/mmu: Set mmio_value to '0' if reserved #PF can't be generatedSean Christopherson1-18/+9
[ Upstream commit 6129ed877d409037b79866327102c9dc59a302fe ] Set the mmio_value to '0' instead of simply clearing the present bit to squash a benign warning in kvm_mmu_set_mmio_spte_mask() that complains about the mmio_value overlapping the lower GFN mask on systems with 52 bits of PA space. Opportunistically clean up the code and comments. Cc: stable@vger.kernel.org Fixes: d43e2675e96fc ("KVM: x86: only do L1TF workaround on affected processors") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200527084909.23492-1-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-25kvm: x86: Fix reserved bits related calculation errors caused by MKTMEKai Huang1-6/+27
[ Upstream commit f3ecb59dd49f1742b97df6ba071aaa3d031154ac ] Intel MKTME repurposes several high bits of physical address as 'keyID' for memory encryption thus effectively reduces platform's maximum physical address bits. Exactly how many bits are reduced is configured by BIOS. To honor such HW behavior, the repurposed bits are reduced from cpuinfo_x86->x86_phys_bits when MKTME is detected in CPU detection. Similarly, AMD SME/SEV also reduces physical address bits for memory encryption, and cpuinfo->x86_phys_bits is reduced too when SME/SEV is detected, so for both MKTME and SME/SEV, boot_cpu_data.x86_phys_bits doesn't hold physical address bits reported by CPUID anymore. Currently KVM treats bits from boot_cpu_data.x86_phys_bits to 51 as reserved bits, but it's not true anymore for MKTME, since MKTME treats those reduced bits as 'keyID', but not reserved bits. Therefore boot_cpu_data.x86_phys_bits cannot be used to calculate reserved bits anymore, although we can still use it for AMD SME/SEV since SME/SEV treats the reduced bits differently -- they are treated as reserved bits, the same as other reserved bits in page table entity [1]. Fix by introducing a new 'shadow_phys_bits' variable in KVM x86 MMU code to store the effective physical bits w/o reserved bits -- for MKTME, it equals to physical address reported by CPUID, and for SME/SEV, it is boot_cpu_data.x86_phys_bits. Note that for the physical address bits reported to guest should remain unchanged -- KVM should report physical address reported by CPUID to guest, but not boot_cpu_data.x86_phys_bits. Because for Intel MKTME, there's no harm if guest sets up 'keyID' bits in guest page table (since MKTME only works at physical address level), and KVM doesn't even expose MKTME to guest. Arguably, for AMD SME/SEV, guest is aware of SEV thus it should adjust boot_cpu_data.x86_phys_bits when it detects SEV, therefore KVM should still reports physcial address reported by CPUID to guest. Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-25kvm: x86: Move kvm_set_mmio_spte_mask() from x86.c to mmu.cKai Huang2-31/+31
[ Upstream commit 7b6f8a06e482960ba6ab06faba51c8f3727a5c7b ] As a prerequisite to fix several SPTE reserved bits related calculation errors caused by MKTME, which requires kvm_set_mmio_spte_mask() to use local static variable defined in mmu.c. Also move call site of kvm_set_mmio_spte_mask() from kvm_arch_init() to kvm_mmu_module_init() so that kvm_set_mmio_spte_mask() can be static. Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-20KVM: nVMX: Consult only the "basic" exit reason when routing nested exitSean Christopherson1-1/+1
commit 2ebac8bb3c2d35f5135466490fc8eeaf3f3e2d37 upstream. Consult only the basic exit reason, i.e. bits 15:0 of vmcs.EXIT_REASON, when determining whether a nested VM-Exit should be reflected into L1 or handled by KVM in L0. For better or worse, the switch statement in nested_vmx_exit_reflected() currently defaults to "true", i.e. reflects any nested VM-Exit without dedicated logic. Because the case statements only contain the basic exit reason, any VM-Exit with modifier bits set will be reflected to L1, even if KVM intended to handle it in L0. Practically speaking, this only affects EXIT_REASON_MCE_DURING_VMENTRY, i.e. a #MC that occurs on nested VM-Enter would be incorrectly routed to L1, as "failed VM-Entry" is the only modifier that KVM can currently encounter. The SMM modifiers will never be generated as KVM doesn't support/employ a SMI Transfer Monitor. Ditto for "exit from enclave", as KVM doesn't yet support virtualizing SGX, i.e. it's impossible to enter an enclave in a KVM guest (L1 or L2). Fixes: 644d711aa0e1 ("KVM: nVMX: Deciding if L0 or L1 should handle an L2 exit") Cc: Jim Mattson <jmattson@google.com> Cc: Xiaoyao Li <xiaoyao.li@intel.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200227174430.26371-1-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-20KVM: nSVM: leave ASID aside in copy_vmcb_control_areaPaolo Bonzini1-1/+1
commit 6c0238c4a62b3a0b1201aeb7e33a4636d552a436 upstream. Restoring the ASID from the hsave area on VMEXIT is wrong, because its value depends on the handling of TLB flushes. Just skipping the field in copy_vmcb_control_area will do. Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-20KVM: nSVM: fix condition for filtering async PFPaolo Bonzini1-2/+2
commit a3535be731c2a343912578465021f50937f7b099 upstream. Async page faults have to be trapped in the host (L1 in this case), since the APF reason was passed from L0 to L1 and stored in the L1 APF data page. This was completely reversed: the page faults were passed to the guest, a L2 hypervisor. Cc: stable@vger.kernel.org Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-20KVM: x86: only do L1TF workaround on affected processorsPaolo Bonzini1-9/+10
[ Upstream commit d43e2675e96fc6ae1a633b6a69d296394448cc32 ] KVM stores the gfn in MMIO SPTEs as a caching optimization. These are split in two parts, as in "[high 11111 low]", to thwart any attempt to use these bits in an L1TF attack. This works as long as there are 5 free bits between MAXPHYADDR and bit 50 (inclusive), leaving bit 51 free so that the MMIO access triggers a reserved-bit-set page fault. The bit positions however were computed wrongly for AMD processors that have encryption support. In this case, x86_phys_bits is reduced (for example from 48 to 43, to account for the C bit at position 47 and four bits used internally to store the SEV ASID and other stuff) while x86_cache_bits in would remain set to 48, and _all_ bits between the reduced MAXPHYADDR and bit 51 are set. Then low_phys_bits would also cover some of the bits that are set in the shadow_mmio_value, terribly confusing the gfn caching mechanism. To fix this, avoid splitting gfns as long as the processor does not have the L1TF bug (which includes all AMD processors). When there is no splitting, low_phys_bits can be set to the reduced MAXPHYADDR removing the overlap. This fixes "npt=0" operation on EPYC processors. Thanks to Maxim Levitsky for bisecting this bug. Cc: stable@vger.kernel.org Fixes: 52918ed5fcf0 ("KVM: SVM: Override default MMIO mask if memory encryption is enabled") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-20KVM: x86/mmu: Consolidate "is MMIO SPTE" codeSean Christopherson1-8/+8
[ Upstream commit 26c44a63a291893e0a00f01e96b6e1d0310a79a9 ] Replace the open-coded "is MMIO SPTE" checks in the MMU warnings related to software-based access/dirty tracking to make the code slightly more self-documenting. No functional change intended. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-20kvm: x86: Fix L1TF mitigation for shadow MMUKai Huang1-5/+13
[ Upstream commit 61455bf26236e7f3d72705382a6437fdfd1bd0af ] Currently KVM sets 5 most significant bits of physical address bits reported by CPUID (boot_cpu_data.x86_phys_bits) for nonpresent or reserved bits SPTE to mitigate L1TF attack from guest when using shadow MMU. However for some particular Intel CPUs the physical address bits of internal cache is greater than physical address bits reported by CPUID. Use the kernel's existing boot_cpu_data.x86_cache_bits to determine the five most significant bits. Doing so improves KVM's L1TF mitigation in the unlikely scenario that system RAM overlaps the high order bits of the "real" physical address space as reported by CPUID. This aligns with the kernel's warnings regarding L1TF mitigation, e.g. in the above scenario the kernel won't warn the user about lack of L1TF mitigation if x86_cache_bits is greater than x86_phys_bits. Also initialize shadow_nonpresent_or_rsvd_mask explicitly to make it consistent with other 'shadow_{xxx}_mask', and opportunistically add a WARN once if KVM's L1TF mitigation cannot be applied on a system that is marked as being susceptible to L1TF. Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-03KVM: VMX: check for existence of secondary exec controls before accessingSean Christopherson1-3/+4
commit fd6b6d9b82f97a851fb0078201ddc38fe9728cda upstream. Return early from vmx_set_virtual_apic_mode() if the processor doesn't support VIRTUALIZE_APIC_ACCESSES or VIRTUALIZE_X2APIC_MODE, both of which reside in SECONDARY_VM_EXEC_CONTROL. This eliminates warnings due to VMWRITEs to SECONDARY_VM_EXEC_CONTROL (VMCS field 401e) failing on processors without secondary exec controls. Remove the similar check for TPR shadowing as it is incorporated in the flexpriority_enabled check and the APIC-related code in vmx_update_msr_bitmap() is further gated by VIRTUALIZE_X2APIC_MODE. Reported-by: Gerhard Wiesinger <redhat@wiesinger.com> Fixes: 8d860bbeedef ("kvm: vmx: Basic APIC virtualization controls have three settings") Cc: Jim Mattson <jmattson@google.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-20KVM: x86: Fix off-by-one error in kvm_vcpu_ioctl_x86_setup_mceJim Mattson1-1/+1
commit c4e0e4ab4cf3ec2b3f0b628ead108d677644ebd9 upstream. Bank_num is a one-based count of banks, not a zero-based index. It overflows the allocated space only when strictly greater than KVM_MAX_MCE_BANKS. Fixes: a9e38c3e01ad ("KVM: x86: Catch potential overrun in MCE setup") Signed-off-by: Jue Wang <juew@google.com> Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Peter Shier <pshier@google.com> Message-Id: <20200511225616.19557-1-jmattson@google.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-02KVM: VMX: Enable machine check support for 32bit targetsUros Bizjak1-1/+1
commit fb56baae5ea509e63c2a068d66a4d8ea91969fca upstream. There is no reason to limit the use of do_machine_check to 64bit targets. MCE handling works for both target familes. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: stable@vger.kernel.org Fixes: a0861c02a981 ("KVM: Add VT-x machine check support") Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Message-Id: <20200414071414.45636-1-ubizjak@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-24kvm: x86: Host feature SSBD doesn't imply guest feature SPEC_CTRL_SSBDJim Mattson1-1/+2
commit 396d2e878f92ec108e4293f1c77ea3bc90b414ff upstream. The host reports support for the synthetic feature X86_FEATURE_SSBD when any of the three following hardware features are set: CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] CPUID.80000008H:EBX.AMD_SSBD[bit 24] CPUID.80000008H:EBX.VIRT_SSBD[bit 25] Either of the first two hardware features implies the existence of the IA32_SPEC_CTRL MSR, but CPUID.80000008H:EBX.VIRT_SSBD[bit 25] does not. Therefore, CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] should only be set in the guest if CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] or CPUID.80000008H:EBX.AMD_SSBD[bit 24] is set on the host. Fixes: 0c54914d0c52a ("KVM: x86: use Intel speculation bugs and features as derived in generic x86 code") Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Jacob Xu <jacobhxu@google.com> Reviewed-by: Peter Shier <pshier@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Reported-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [bwh: Backported to 4.x: adjust indentation] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>
generated by cgit v1.2.3 (git 2.39.0) at 2025-09-26 10:10:08 +0300