[PATCH Part2 RFC v3 18/37] KVM: SVM: Add initial SEV-SNP support
From: Brijesh Singh <hidden>
Date: 2021-06-02 14:16:44
Also in:
linux-coco, 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
The next generation of SEV is called SEV-SNP (Secure Nested Paging). SEV-SNP builds upon existing SEV and SEV-ES functionality while adding new hardware based security protection. SEV-SNP adds strong memory encryption integrity protection to help prevent malicious hypervisor-based attacks such as data replay, memory re-mapping, and more, to create an isolated execution environment. The SNP feature can be enabled in the KVM by passing the sev-snp module parameter. Signed-off-by: Brijesh Singh <redacted> --- arch/x86/kvm/svm/sev.c | 18 ++++++++++++++++++ arch/x86/kvm/svm/svm.h | 12 ++++++++++++ 2 files changed, 30 insertions(+)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 411ed72f63af..abca2b9dee83 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c@@ -52,9 +52,14 @@ module_param_named(sev, sev_enabled, bool, 0444); /* enable/disable SEV-ES support */ static bool sev_es_enabled = true; module_param_named(sev_es, sev_es_enabled, bool, 0444); + +/* enable/disable SEV-SNP support */ +static bool sev_snp_enabled = true; +module_param_named(sev_snp, sev_snp_enabled, bool, 0444); #else #define sev_enabled false #define sev_es_enabled false +#define sev_snp_enabled false #endif /* CONFIG_KVM_AMD_SEV */ #define AP_RESET_HOLD_NONE 0
@@ -1825,6 +1830,7 @@ void __init sev_hardware_setup(void) { #ifdef CONFIG_KVM_AMD_SEV unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count; + bool sev_snp_supported = false; bool sev_es_supported = false; bool sev_supported = false;
@@ -1888,9 +1894,21 @@ void __init sev_hardware_setup(void) pr_info("SEV-ES supported: %u ASIDs\n", sev_es_asid_count); sev_es_supported = true; + /* SEV-SNP support requested? */ + if (!sev_snp_enabled) + goto out; + + /* Is SEV-SNP enabled? */ + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) + goto out; + + pr_info("SEV-SNP supported: %u ASIDs\n", min_sev_asid - 1); + sev_snp_supported = true; + out: sev_enabled = sev_supported; sev_es_enabled = sev_es_supported; + sev_snp_enabled = sev_snp_supported; #endif }
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 1175edb02d33..b9ea99f8579e 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h@@ -58,6 +58,7 @@ enum { struct kvm_sev_info { bool active; /* SEV enabled guest */ bool es_active; /* SEV-ES enabled guest */ + bool snp_active; /* SEV-SNP enabled guest */ unsigned int asid; /* ASID used for this guest */ unsigned int handle; /* SEV firmware handle */ int fd; /* SEV device fd */
@@ -232,6 +233,17 @@ static inline bool sev_es_guest(struct kvm *kvm) #endif } +static inline bool sev_snp_guest(struct kvm *kvm) +{ +#ifdef CONFIG_KVM_AMD_SEV + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + + return sev_es_guest(kvm) && sev->snp_active; +#else + return false; +#endif +} + static inline void vmcb_mark_all_dirty(struct vmcb *vmcb) { vmcb->control.clean = 0;
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2.17.1