[PATCH Part2 v5 36/45] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT
From: Brijesh Singh <hidden>
Date: 2021-08-20 16:02:45
Also in:
kvm, linux-crypto, linux-mm, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
SEV-SNP guests are required to perform a GHCB GPA registration. Before using a GHCB GPA for a vCPU the first time, a guest must register the vCPU GHCB GPA. If hypervisor can work with the guest requested GPA then it must respond back with the same GPA otherwise return -1. On VMEXIT, Verify that GHCB GPA matches with the registered value. If a mismatch is detected then abort the guest. Signed-off-by: Brijesh Singh <redacted> --- arch/x86/include/asm/sev-common.h | 8 ++++++++ arch/x86/kvm/svm/sev.c | 27 +++++++++++++++++++++++++++ arch/x86/kvm/svm/svm.h | 7 +++++++ 3 files changed, 42 insertions(+)
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 779c7e8f836c..91089967ab09 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h@@ -59,6 +59,14 @@ #define GHCB_MSR_AP_RESET_HOLD_RESULT_POS 12 #define GHCB_MSR_AP_RESET_HOLD_RESULT_MASK GENMASK_ULL(51, 0) +/* Preferred GHCB GPA Request */ +#define GHCB_MSR_PREF_GPA_REQ 0x010 +#define GHCB_MSR_GPA_VALUE_POS 12 +#define GHCB_MSR_GPA_VALUE_MASK GENMASK_ULL(51, 0) + +#define GHCB_MSR_PREF_GPA_RESP 0x011 +#define GHCB_MSR_PREF_GPA_NONE 0xfffffffffffff + /* GHCB GPA Register */ #define GHCB_MSR_REG_GPA_REQ 0x012 #define GHCB_MSR_REG_GPA_REQ_VAL(v) \
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index c41d972dadc3..991b8c996fc1 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c@@ -2984,6 +2984,27 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm) GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS); break; } + case GHCB_MSR_PREF_GPA_REQ: { + set_ghcb_msr_bits(svm, GHCB_MSR_PREF_GPA_NONE, GHCB_MSR_GPA_VALUE_MASK, + GHCB_MSR_GPA_VALUE_POS); + set_ghcb_msr_bits(svm, GHCB_MSR_PREF_GPA_RESP, GHCB_MSR_INFO_MASK, + GHCB_MSR_INFO_POS); + break; + } + case GHCB_MSR_REG_GPA_REQ: { + u64 gfn; + + gfn = get_ghcb_msr_bits(svm, GHCB_MSR_GPA_VALUE_MASK, + GHCB_MSR_GPA_VALUE_POS); + + svm->ghcb_registered_gpa = gfn_to_gpa(gfn); + + set_ghcb_msr_bits(svm, gfn, GHCB_MSR_GPA_VALUE_MASK, + GHCB_MSR_GPA_VALUE_POS); + set_ghcb_msr_bits(svm, GHCB_MSR_REG_GPA_RESP, GHCB_MSR_INFO_MASK, + GHCB_MSR_INFO_POS); + break; + } case GHCB_MSR_TERM_REQ: { u64 reason_set, reason_code;
@@ -3024,6 +3045,12 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu) return -EINVAL; } + /* SEV-SNP guest requires that the GHCB GPA must be registered */ + if (sev_snp_guest(svm->vcpu.kvm) && !ghcb_gpa_is_registered(svm, ghcb_gpa)) { + vcpu_unimpl(&svm->vcpu, "vmgexit: GHCB GPA [%#llx] is not registered.\n", ghcb_gpa); + return -EINVAL; + } + ret = sev_es_validate_vmgexit(svm, &exit_code); if (ret) return ret;
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 22c01d958898..d10f7166b39d 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h@@ -210,6 +210,8 @@ struct vcpu_svm { */ u64 ghcb_sw_exit_info_1; u64 ghcb_sw_exit_info_2; + + u64 ghcb_registered_gpa; }; struct svm_cpu_data {
@@ -266,6 +268,11 @@ static inline bool sev_snp_guest(struct kvm *kvm) return sev_es_guest(kvm) && sev->snp_active; } +static inline bool ghcb_gpa_is_registered(struct vcpu_svm *svm, u64 val) +{ + return svm->ghcb_registered_gpa == val; +} + static inline void vmcb_mark_all_dirty(struct vmcb *vmcb) { vmcb->control.clean = 0;
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2.17.1