diff options
| author | Tom Lendacky <thomas.lendacky@amd.com> | 2020-12-10 11:09:57 -0600 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-12-15 05:20:53 -0500 |
| commit | 5b51cb13160ae0ba10645bd0a84e7847677fb6a0 (patch) | |
| tree | 8dc59f3ad724d8a4f586d6d44a41fb3c1aa6c9ce /arch/x86/kvm | |
| parent | f27ad38aac23263c40fe26c0188182c129a8f8dd (diff) | |
KVM: SVM: Add support for CR4 write traps for an SEV-ES guest
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: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <c3880bf2db8693aa26f648528fbc6e967ab46e25.1607620209.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 7 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 16 |
2 files changed, 19 insertions, 4 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index ddcb7390bb0e..4b3d935a1325 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2466,6 +2466,12 @@ static int cr_trap(struct vcpu_svm *svm) kvm_post_set_cr0(vcpu, old_value, new_value); break; + case 4: + old_value = kvm_read_cr4(vcpu); + svm_set_cr4(vcpu, new_value); + + kvm_post_set_cr4(vcpu, old_value, new_value); + break; default: WARN(1, "unhandled CR%d write trap", cr); kvm_queue_exception(vcpu, UD_VECTOR); @@ -3023,6 +3029,7 @@ static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = { [SVM_EXIT_RDPRU] = rdpru_interception, [SVM_EXIT_EFER_WRITE_TRAP] = efer_trap, [SVM_EXIT_CR0_WRITE_TRAP] = cr_trap, + [SVM_EXIT_CR4_WRITE_TRAP] = cr_trap, [SVM_EXIT_INVPCID] = invpcid_interception, [SVM_EXIT_NPF] = npf_interception, [SVM_EXIT_RSM] = rsm_interception, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index efa70e30d23f..c3686233508b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -983,12 +983,22 @@ bool kvm_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) } EXPORT_SYMBOL_GPL(kvm_is_valid_cr4); +void kvm_post_set_cr4(struct kvm_vcpu *vcpu, unsigned long old_cr4, unsigned long cr4) +{ + unsigned long mmu_role_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE | + X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE; + + if (((cr4 ^ old_cr4) & mmu_role_bits) || + (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE))) + kvm_mmu_reset_context(vcpu); +} +EXPORT_SYMBOL_GPL(kvm_post_set_cr4); + int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) { unsigned long old_cr4 = kvm_read_cr4(vcpu); unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE | X86_CR4_SMEP; - unsigned long mmu_role_bits = pdptr_bits | X86_CR4_SMAP | X86_CR4_PKE; if (!kvm_is_valid_cr4(vcpu, cr4)) return 1; @@ -1015,9 +1025,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) kvm_x86_ops.set_cr4(vcpu, cr4); - if (((cr4 ^ old_cr4) & mmu_role_bits) || - (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE))) - kvm_mmu_reset_context(vcpu); + kvm_post_set_cr4(vcpu, old_cr4, cr4); return 0; } |