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| author | Brijesh Singh <brijesh.singh@amd.com> | 2018-02-19 19:14:44 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-02-24 04:24:12 +0300 |
| commit | 7607b7174405aec7441ff6c970833c463114040a (patch) | |
| tree | b507a9bd87b758a01a532ac98814f614bffd3b38 /arch/x86/kvm/svm.c | |
| parent | 3e233385ef4a217a2812115ed84d4be36eb16817 (diff) | |
| download | linux-7607b7174405aec7441ff6c970833c463114040a.tar.xz | |
KVM: SVM: install RSM intercept
RSM instruction is used by the SMM handler to return from SMM mode.
Currently, rsm causes a #UD - which results in instruction fetch, decode,
and emulate. By installing the RSM intercept we can avoid the instruction
fetch since we know that #VMEXIT was due to rsm.
The patch is required for the SEV guest, because in case of SEV guest
memory is encrypted with guest-specific key and hypervisor will not
able to fetch the instruction bytes from the guest memory.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index ca69d53d7e6d..4aeb665ffbb0 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -300,6 +300,8 @@ module_param(vgif, int, 0444); static int sev = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT); module_param(sev, int, 0444); +static u8 rsm_ins_bytes[] = "\x0f\xaa"; + static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0); static void svm_flush_tlb(struct kvm_vcpu *vcpu, bool invalidate_gpa); static void svm_complete_interrupts(struct vcpu_svm *svm); @@ -1383,6 +1385,7 @@ static void init_vmcb(struct vcpu_svm *svm) set_intercept(svm, INTERCEPT_SKINIT); set_intercept(svm, INTERCEPT_WBINVD); set_intercept(svm, INTERCEPT_XSETBV); + set_intercept(svm, INTERCEPT_RSM); if (!kvm_mwait_in_guest()) { set_intercept(svm, INTERCEPT_MONITOR); @@ -3699,6 +3702,12 @@ static int emulate_on_interception(struct vcpu_svm *svm) return emulate_instruction(&svm->vcpu, 0) == EMULATE_DONE; } +static int rsm_interception(struct vcpu_svm *svm) +{ + return x86_emulate_instruction(&svm->vcpu, 0, 0, + rsm_ins_bytes, 2) == EMULATE_DONE; +} + static int rdpmc_interception(struct vcpu_svm *svm) { int err; @@ -4541,7 +4550,7 @@ static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = { [SVM_EXIT_MWAIT] = mwait_interception, [SVM_EXIT_XSETBV] = xsetbv_interception, [SVM_EXIT_NPF] = npf_interception, - [SVM_EXIT_RSM] = emulate_on_interception, + [SVM_EXIT_RSM] = rsm_interception, [SVM_EXIT_AVIC_INCOMPLETE_IPI] = avic_incomplete_ipi_interception, [SVM_EXIT_AVIC_UNACCELERATED_ACCESS] = avic_unaccelerated_access_interception, }; |