- 15 Dec, 2020 24 commits
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Tom Lendacky authored
The GHCB specification defines how NMIs are to be handled for an SEV-ES guest. To detect the completion of an NMI the hypervisor must not intercept the IRET instruction (because a #VC while running the NMI will issue an IRET) and, instead, must receive an NMI Complete exit event from the guest. Update the KVM support for detecting the completion of NMIs in the guest to follow the GHCB specification. When an SEV-ES guest is active, the IRET instruction will no longer be intercepted. Now, when the NMI Complete exit event is received, the iret_interception() function will be called to simulate the completion of the NMI. Signed-off-by:
Tom Lendacky <thomas.lendacky@amd.com> Message-Id: <5ea3dd69b8d4396cefdc9048ebc1ab7caa70a847.1607620209.git.thomas.lendacky@amd.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Tom Lendacky authored
The guest FPU state is automatically restored on VMRUN and saved on VMEXIT by the hardware, so there is no reason to do this in KVM. Eliminate the allocation of the guest_fpu save area and key off that to skip operations related to the guest FPU state. Signed-off-by:
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Tom Lendacky authored
SEV-ES guests do not currently support SMM. Update the has_emulated_msr() kvm_x86_ops function to take a struct kvm parameter so that the capability can be reported at a VM level. Since this op is also called during KVM initialization and before a struct kvm instance is available, comments will be added to each implementation of has_emulated_msr() to indicate the kvm parameter can be null. Signed-off-by:
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Tom Lendacky authored
Since many of the registers used by the SEV-ES are encrypted and cannot be read or written, adjust the __get_sregs() / __set_sregs() to take into account whether the VMSA/guest state is encrypted. For __get_sregs(), return the actual value that is in use by the guest for all registers being tracked using the write trap support. For __set_sregs(), skip setting of all guest registers values. Signed-off-by:
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Tom Lendacky authored
For SEV-ES guests, the interception of control register write access is not recommended. Control register interception occurs prior to the control register being modified and the hypervisor is unable to modify the control register itself because the register is located in the encrypted register state. SEV-ES guests introduce new control register write traps. These traps provide intercept support of a control register write after the control register has been modified. The new control register value is provided in the VMCB EXITINFO1 field, allowing the hypervisor to track the setting of the guest control registers. Add support to track the value of the guest CR8 register using the control register write trap so that the hypervisor understands the guest operating mode. Signed-off-by:
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Tom Lendacky authored
For SEV-ES guests, the interception of control register write access is not recommended. Control register interception occurs prior to the control register being modified and the hypervisor is unable to modify the control register itself because the register is located in the encrypted register state. SEV-ES guests introduce new control register write traps. These traps provide intercept support of a control register write after the control register has been modified. The new control register value is provided in the VMCB EXITINFO1 field, allowing the hypervisor to track the setting of the guest control registers. Add support to track the value of the guest CR4 register using the control register write trap so that the hypervisor understands the guest operating mode. Signed-off-by:
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Tom Lendacky authored
For SEV-ES guests, the interception of control register write access is not recommended. Control register interception occurs prior to the control register being modified and the hypervisor is unable to modify the control register itself because the register is located in the encrypted register state. SEV-ES support introduces new control register write traps. These traps provide intercept support of a control register write after the control register has been modified. The new control register value is provided in the VMCB EXITINFO1 field, allowing the hypervisor to track the setting of the guest control registers. Add support to track the value of the guest CR0 register using the control register write trap so that the hypervisor understands the guest operating mode. Signed-off-by:
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Tom Lendacky authored
For SEV-ES guests, the interception of EFER write access is not recommended. EFER interception occurs prior to EFER being modified and the hypervisor is unable to modify EFER itself because the register is located in the encrypted register state. SEV-ES support introduces a new EFER write trap. This trap provides intercept support of an EFER write after it has been modified. The new EFER value is provided in the VMCB EXITINFO1 field, allowing the hypervisor to track the setting of the guest EFER. Add support to track the value of the guest EFER value using the EFER write trap so that the hypervisor understands the guest operating mode. Signed-off-by:
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Tom Lendacky authored
For an SEV-ES guest, string-based port IO is performed to a shared (un-encrypted) page so that both the hypervisor and guest can read or write to it and each see the contents. For string-based port IO operations, invoke SEV-ES specific routines that can complete the operation using common KVM port IO support. Signed-off-by:
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Tom Lendacky authored
For an SEV-ES guest, MMIO is performed to a shared (un-encrypted) page so that both the hypervisor and guest can read or write to it and each see the contents. The GHCB specification provides software-defined VMGEXIT exit codes to indicate a request for an MMIO read or an MMIO write. Add support to recognize the MMIO requests and invoke SEV-ES specific routines that can complete the MMIO operation. These routines use common KVM support to complete the MMIO operation. Signed-off-by:
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Tom Lendacky authored
Add trace events for entry to and exit from VMGEXIT MSR protocol processing. The vCPU will be common for the trace events. The MSR protocol processing is guided by the GHCB GPA in the VMCB, so the GHCB GPA will represent the input and output values for the entry and exit events, respectively. Additionally, the exit event will contain the return code for the event. Signed-off-by:
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Tom Lendacky authored
Add trace events for entry to and exit from VMGEXIT processing. The vCPU id and the exit reason will be common for the trace events. The exit info fields will represent the input and output values for the entry and exit events, respectively. Signed-off-by:
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Tom Lendacky authored
The GHCB specification defines a GHCB MSR protocol using the lower 12-bits of the GHCB MSR (in the hypervisor this corresponds to the GHCB GPA field in the VMCB). Function 0x100 is a request for termination of the guest. The guest has encountered some situation for which it has requested to be terminated. The GHCB MSR value contains the reason for the request. Signed-off-by:
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Tom Lendacky authored
The GHCB specification defines a GHCB MSR protocol using the lower 12-bits of the GHCB MSR (in the hypervisor this corresponds to the GHCB GPA field in the VMCB). Function 0x004 is a request for CPUID information. Only a single CPUID result register can be sent per invocation, so the protocol defines the register that is requested. The GHCB MSR value is set to the CPUID register value as per the specification via the VMCB GHCB GPA field. Signed-off-by:
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Tom Lendacky authored
The GHCB specification defines a GHCB MSR protocol using the lower 12-bits of the GHCB MSR (in the hypervisor this corresponds to the GHCB GPA field in the VMCB). Function 0x002 is a request to set the GHCB MSR value to the SEV INFO as per the specification via the VMCB GHCB GPA field. Signed-off-by:
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Tom Lendacky authored
SEV-ES adds a new VMEXIT reason code, VMGEXIT. Initial support for a VMGEXIT includes mapping the GHCB based on the guest GPA, which is obtained from a new VMCB field, and then validating the required inputs for the VMGEXIT exit reason. Since many of the VMGEXIT exit reasons correspond to existing VMEXIT reasons, the information from the GHCB is copied into the VMCB control exit code areas and KVM register areas. The standard exit handlers are invoked, similar to standard VMEXIT processing. Before restarting the vCPU, the GHCB is updated with any registers that have been updated by the hypervisor. Signed-off-by:
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Tom Lendacky authored
This is a pre-patch to consolidate some exit handling code into callable functions. Follow-on patches for SEV-ES exit handling will then be able to use them from the sev.c file. Signed-off-by:
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Tom Lendacky authored
When a SHUTDOWN VMEXIT is encountered, normally the VMCB is re-initialized so that the guest can be re-launched. But when a guest is running as an SEV-ES guest, the VMSA cannot be re-initialized because it has been encrypted. For now, just return -EINVAL to prevent a possible attempt at a guest reset. Signed-off-by:
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Tom Lendacky authored
When a guest is running as an SEV-ES guest, it is not possible to emulate instructions. Add support to prevent instruction emulation. Signed-off-by:
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Tom Lendacky authored
Since the guest register state of an SEV-ES guest is encrypted, debugging is not supported. Update the code to prevent guest debugging when the guest has protected state. Additionally, an SEV-ES guest must only and always intercept DR7 reads and writes. Update set_dr_intercepts() and clr_dr_intercepts() to account for this. Signed-off-by:
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Tom Lendacky authored
When a guest is running under SEV-ES, the hypervisor cannot access the guest register state. There are numerous places in the KVM code where certain registers are accessed that are not allowed to be accessed (e.g. RIP, CR0, etc). Add checks to prevent register accesses and add intercept update support at various points within the KVM code. Also, when handling a VMGEXIT, exceptions are passed back through the GHCB. Since the RDMSR/WRMSR intercepts (may) inject a #GP on error, update the SVM intercepts to handle this for SEV-ES guests. Signed-off-by:
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Paolo Bonzini authored
This will be used by SEV-ES to inject MSR failure via the GHCB. Reviewed-by:
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Paolo Bonzini authored
Simplify the four functions that handle {kernel,user} {rd,wr}msr, there is still some repetition between the two instances of rdmsr but the whole business of calling kvm_inject_gp and kvm_skip_emulated_instruction can be unified nicely. Because complete_emulated_wrmsr now becomes essentially a call to kvm_complete_insn_gp, remove complete_emulated_msr. Reviewed-by: -
Paolo Bonzini authored
There is no need to inject a #GP from kvm_mtrr_set_msr, kvm_emulate_wrmsr will handle it. Reviewed-by:
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- 14 Dec, 2020 7 commits
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Tom Lendacky authored
When performing VMGEXIT processing for an SEV-ES guest, register values will be synced between KVM and the GHCB. Prepare for detecting when a GPR has been updated (marked dirty) in order to determine whether to sync the register to the GHCB. Signed-off-by:
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Tom Lendacky authored
Allocate a page during vCPU creation to be used as the encrypted VM save area (VMSA) for the SEV-ES guest. Provide a flag in the kvm_vcpu_arch structure that indicates whether the guest state is protected. When freeing a VMSA page that has been encrypted, the cache contents must be flushed using the MSR_AMD64_VM_PAGE_FLUSH before freeing the page. [ i386 build warnings ] Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
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Tom Lendacky authored
Update the GHCB accessor functions to add functions for retrieve GHCB fields by name. Update existing code to use the new accessor functions. Signed-off-by:
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Tom Lendacky authored
Add support to KVM for determining if a system is capable of supporting SEV-ES as well as determining if a guest is an SEV-ES guest. Signed-off-by:
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Tom Lendacky authored
When both KVM support and the CCP driver are built into the kernel instead of as modules, KVM initialization can happen before CCP initialization. As a result, sev_platform_status() will return a failure when it is called from sev_hardware_setup(), when this isn't really an error condition. Since sev_platform_status() doesn't need to be called at this time anyway, remove the invocation from sev_hardware_setup(). Signed-off-by:
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Tom Lendacky authored
On systems that do not have hardware enforced cache coherency between encrypted and unencrypted mappings of the same physical page, the hypervisor can use the VM page flush MSR (0xc001011e) to flush the cache contents of an SEV guest page. When a small number of pages are being flushed, this can be used in place of issuing a WBINVD across all CPUs. CPUID 0x8000001f_eax[2] is used to determine if the VM page flush MSR is available. Add a CPUID feature to indicate it is supported and define the MSR. Signed-off-by:
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Uros Bizjak authored
Move kvm_machine_check to x86.h to avoid two exact copies of the same function in kvm.c and svm.c. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:
Uros Bizjak <ubizjak@gmail.com> Message-Id: <20201029135600.122392-1-ubizjak@gmail.com> Signed-off-by:
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- 12 Dec, 2020 7 commits
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Paolo Bonzini authored
Merge tag 'kvm-s390-next-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD KVM: s390: Features and Test for 5.11 - memcg accouting for s390 specific parts of kvm and gmap - selftest for diag318 - new kvm_stat for when async_pf falls back to sync The selftest even triggers a non-critical bug that is unrelated to diag318, fix will follow later.
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Paolo Bonzini authored
Until commit e7c587da ("x86/speculation: Use synthetic bits for IBRS/IBPB/STIBP"), KVM was testing both Intel and AMD CPUID bits before allowing the guest to write MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD. Testing only Intel bits on VMX processors, or only AMD bits on SVM processors, fails if the guests are created with the "opposite" vendor as the host. While at it, also tweak the host CPU check to use the vendor-agnostic feature bit X86_FEATURE_IBPB, since we only care about the availability of the MSR on the host here and not about specific CPUID bits. Fixes: e7c587da ("x86/speculation: Use synthetic bits for IBRS/IBPB/STIBP") Cc: stable@vger.kernel.org Reported-by:
Denis V. Lunev <den@openvz.org> Signed-off-by:
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Cathy Zhang authored
AVX512_FP16 is supported by Intel processors, like Sapphire Rapids. It could gain better performance for it's faster compared to FP32 if the precision or magnitude requirements are met. It's availability is indicated by CPUID.(EAX=7,ECX=0):EDX[bit 23]. Expose it in KVM supported CPUID, then guest could make use of it; no new registers are used, only new instructions. Signed-off-by:
Cathy Zhang <cathy.zhang@intel.com> Signed-off-by:
Kyung Min Park <kyung.min.park@intel.com> Acked-by:
Dave Hansen <dave.hansen@intel.com> Reviewed-by:
Tony Luck <tony.luck@intel.com> Message-Id: <20201208033441.28207-3-kyung.min.park@intel.com> Signed-off-by:
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Kyung Min Park authored
Enumerate AVX512 Half-precision floating point (FP16) CPUID feature flag. Compared with using FP32, using FP16 cut the number of bits required for storage in half, reducing the exponent from 8 bits to 5, and the mantissa from 23 bits to 10. Using FP16 also enables developers to train and run inference on deep learning models fast when all precision or magnitude (FP32) is not needed. A processor supports AVX512 FP16 if CPUID.(EAX=7,ECX=0):EDX[bit 23] is present. The AVX512 FP16 requires AVX512BW feature be implemented since the instructions for manipulating 32bit masks are associated with AVX512BW. The only in-kernel usage of this is kvm passthrough. The CPU feature flag is shown as "avx512_fp16" in /proc/cpuinfo. Signed-off-by:
Borislav Petkov <bp@suse.de> Signed-off-by:
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Aaron Lewis authored
Both user_msr_test and userspace_msr_exit_test tests the functionality of kvm_msr_filter. Instead of testing this feature in two tests, merge them together, so there is only one test for this feature. Signed-off-by:
Aaron Lewis <aaronlewis@google.com> Message-Id: <20201204172530.2958493-1-aaronlewis@google.com> Signed-off-by:
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Aaron Lewis authored
Add a selftest to test that when the ioctl KVM_X86_SET_MSR_FILTER is called with an MSR list, those MSRs exit to userspace. This test uses 3 MSRs to test this: 1. MSR_IA32_XSS, an MSR the kernel knows about. 2. MSR_IA32_FLUSH_CMD, an MSR the kernel does not know about. 3. MSR_NON_EXISTENT, an MSR invented in this test for the purposes of passing a fake MSR from the guest to userspace. KVM just acts as a pass through. Userspace is also able to inject a #GP. This is demonstrated when MSR_IA32_XSS and MSR_IA32_FLUSH_CMD are misused in the test. When this happens a #GP is initiated in userspace to be thrown in the guest which is handled gracefully by the exception handling framework introduced earlier in this series. Tests for the generic instruction emulator were also added. For this to work the module parameter kvm.force_emulation_prefix=1 has to be enabled. If it isn't enabled the tests will be skipped. A test was also added to ensure the MSR permission bitmap is being set correctly by executing reads and writes of MSR_FS_BASE and MSR_GS_BASE in the guest while alternating which MSR userspace should intercept. If the permission bitmap is being set correctly only one of the MSRs should be coming through at a time, and the guest should be able to read and write the other one directly. Signed-off-by:Alexander Graf <graf@amazon.com> Message-Id: <20201012194716.3950330-5-aaronlewis@google.com> Signed-off-by:
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Uros Bizjak authored
Saves one byte in __vmx_vcpu_run for the same functionality. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:
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- 10 Dec, 2020 2 commits
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Christian Borntraeger authored
Right now we do count pfault (pseudo page faults aka async page faults start and completion events). What we do not count is, if an async page fault would have been possible by the host, but it was disabled by the guest (e.g. interrupts off, pfault disabled, secure execution....). Let us count those as well in the pfault_sync counter. Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
Cornelia Huck <cohuck@redhat.com> Link: https://lore.kernel.org/r/20201125090658.38463-1-borntraeger@de.ibm.com
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Collin Walling authored
The DIAGNOSE 0x0318 instruction, unique to s390x, is a privileged call that must be intercepted via SIE, handled in userspace, and the information set by the instruction is communicated back to KVM. To test the instruction interception, an ad-hoc handler is defined which simply has a VM execute the instruction and then userspace will extract the necessary info. The handler is defined such that the instruction invocation occurs only once. It is up to the caller to determine how the info returned by this handler should be used. The diag318 info is communicated from userspace to KVM via a sync_regs call. This is tested during a sync_regs test, where the diag318 info is requested via the handler, then the info is stored in the appropriate register in KVM via a sync registers call. If KVM does not support diag318, then the tests will print a message stating that diag318 was skipped, and the asserts will simply test against a value of 0. Signed-off-by:
Collin Walling <walling@linux.ibm.com> Link: https://lore.kernel.org/r/20201207154125.10322-1-walling@linux.ibm.comAcked-by:
Janosch Frank <frankja@linux.ibm.com> Acked-by:
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