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.
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Joerg Roedel <jroe...@suse.de>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Tony Luck <tony.l...@intel.com>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: "Peter Zijlstra (Intel)" <pet...@infradead.org>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: David Rientjes <rient...@google.com>
Cc: Sean Christopherson <sea...@google.com>
Cc: x...@kernel.org
Cc: k...@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
---
arch/x86/kvm/svm/sev.c | 17 +++++++++++++++++
arch/x86/kvm/svm/svm.c | 5 +++++
arch/x86/kvm/svm/svm.h | 13 +++++++++++++
3 files changed, 35 insertions(+)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 48017fef1cd9..b720837faf5a 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -19,6 +19,7 @@
#include <asm/fpu/internal.h>
#include <asm/trapnr.h>
+#include <asm/sev-snp.h>
#include "x86.h"
#include "svm.h"
@@ -1249,6 +1250,7 @@ void sev_vm_destroy(struct kvm *kvm)
void __init sev_hardware_setup(void)
{
unsigned int eax, ebx, ecx, edx;
+ bool sev_snp_supported = false;
bool sev_es_supported = false;
bool sev_supported = false;
@@ -1298,9 +1300,24 @@ void __init sev_hardware_setup(void)
pr_info("SEV-ES supported: %u ASIDs\n", min_sev_asid - 1);
sev_es_supported = true;
+ /* SEV-SNP support requested? */
+ if (!sev_snp)
+ goto out;
+
+ /* Does the CPU support SEV-SNP? */
+ if (!boot_cpu_has(X86_FEATURE_SEV_SNP))
+ goto out;
+
+ if (!snp_key_active())
+ goto out;
+
+ pr_info("SEV-SNP supported: %u ASIDs\n", min_sev_asid - 1);
+ sev_snp_supported = true;
+
out:
sev = sev_supported;
sev_es = sev_es_supported;
+ sev_snp = sev_snp_supported;
}
void sev_hardware_teardown(void)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 3442d44ca53b..aa7ff4685c87 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -197,6 +197,10 @@ module_param(sev, int, 0444);
int sev_es = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
module_param(sev_es, int, 0444);
+/* enable/disable SEV-SNP support */
+int sev_snp = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
+module_param(sev_snp, int, 0444);
+
bool __read_mostly dump_invalid_vmcb;
module_param(dump_invalid_vmcb, bool, 0644);
@@ -986,6 +990,7 @@ static __init int svm_hardware_setup(void)
} else {
sev = false;
sev_es = false;
+ sev_snp = false;
}
svm_adjust_mmio_mask();
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 6e7d070f8b86..3dd60d2a567a 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -73,6 +73,7 @@ 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 */
@@ -241,6 +242,17 @@ 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;
@@ -407,6 +419,7 @@ static inline bool gif_set(struct vcpu_svm *svm)
extern int sev;
extern int sev_es;
+extern int sev_snp;
extern bool dump_invalid_vmcb;
u32 svm_msrpm_offset(u32 msr);
--
2.17.1
