[RFC,02/35] KVM: SVM: Add support for SEV-ES capability in KVM

Commit Message

Tom Lendacky Sept. 14, 2020, 8:15 p.m. UTC

From: Tom Lendacky <[e-mail]>

Add support to KVM for determining if a system is capable of supporting
SEV-ES as well as determining if a guest is an SEV-ES guest.

Signed-off-by: Tom Lendacky <[e-mail]>
---
 arch/x86/kvm/Kconfig   |  3 ++-
 arch/x86/kvm/svm/sev.c | 47 ++++++++++++++++++++++++++++++++++--------
 arch/x86/kvm/svm/svm.c | 20 +++++++++---------
 arch/x86/kvm/svm/svm.h | 17 ++++++++++++++-
 4 files changed, 66 insertions(+), 21 deletions(-)

Patch

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index fbd5bd7a945a..4e8924aab05e 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -99,7 +99,8 @@  config KVM_AMD_SEV
 	depends on KVM_AMD && X86_64
 	depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
 	help
-	Provides support for launching Encrypted VMs on AMD processors.
+	  Provides support for launching Encrypted VMs (SEV) and Encrypted VMs
+	  with Encrypted State (SEV-ES) on AMD processors.
 
 config KVM_MMU_AUDIT
 	bool "Audit KVM MMU"
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index fab382e2dad2..48379e21ed43 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -923,7 +923,7 @@  int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 	struct kvm_sev_cmd sev_cmd;
 	int r;
 
-	if (!svm_sev_enabled())
+	if (!svm_sev_enabled() || !sev)
 		return -ENOTTY;
 
 	if (!argp)
@@ -1115,29 +1115,58 @@  void sev_vm_destroy(struct kvm *kvm)
 	sev_asid_free(sev->asid);
 }
 
-int __init sev_hardware_setup(void)
+void __init sev_hardware_setup(void)
 {
+	unsigned int eax, ebx, ecx, edx;
+	bool sev_es_supported = false;
+	bool sev_supported = false;
+
+	/* Does the CPU support SEV? */
+	if (!boot_cpu_has(X86_FEATURE_SEV))
+		goto out;
+
+	/* Retrieve SEV CPUID information */
+	cpuid(0x8000001f, &eax, &ebx, &ecx, &edx);
+
 	/* Maximum number of encrypted guests supported simultaneously */
-	max_sev_asid = cpuid_ecx(0x8000001F);
+	max_sev_asid = ecx;
 
 	if (!svm_sev_enabled())
-		return 1;
+		goto out;
 
 	/* Minimum ASID value that should be used for SEV guest */
-	min_sev_asid = cpuid_edx(0x8000001F);
+	min_sev_asid = edx;
 
 	/* Initialize SEV ASID bitmaps */
 	sev_asid_bitmap = bitmap_zalloc(max_sev_asid, GFP_KERNEL);
 	if (!sev_asid_bitmap)
-		return 1;
+		goto out;
 
 	sev_reclaim_asid_bitmap = bitmap_zalloc(max_sev_asid, GFP_KERNEL);
 	if (!sev_reclaim_asid_bitmap)
-		return 1;
+		goto out;
 
-	pr_info("SEV supported\n");
+	pr_info("SEV supported: %u ASIDs\n", max_sev_asid - min_sev_asid + 1);
+	sev_supported = true;
 
-	return 0;
+	/* SEV-ES support requested? */
+	if (!sev_es)
+		goto out;
+
+	/* Does the CPU support SEV-ES? */
+	if (!boot_cpu_has(X86_FEATURE_SEV_ES))
+		goto out;
+
+	/* Has the system been allocated ASIDs for SEV-ES? */
+	if (min_sev_asid == 1)
+		goto out;
+
+	pr_info("SEV-ES supported: %u ASIDs\n", min_sev_asid - 1);
+	sev_es_supported = true;
+
+out:
+	sev = sev_supported;
+	sev_es = sev_es_supported;
 }
 
 void sev_hardware_teardown(void)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4368b66615c1..83292fc44b4e 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -187,9 +187,13 @@  static int vgif = true;
 module_param(vgif, int, 0444);
 
 /* enable/disable SEV support */
-static int sev = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
+int sev = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
 module_param(sev, int, 0444);
 
+/* enable/disable SEV-ES support */
+int sev_es = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
+module_param(sev_es, int, 0444);
+
 static bool __read_mostly dump_invalid_vmcb = 0;
 module_param(dump_invalid_vmcb, bool, 0644);
 
@@ -860,15 +864,11 @@  static __init int svm_hardware_setup(void)
 		kvm_enable_efer_bits(EFER_SVME | EFER_LMSLE);
 	}
 
-	if (sev) {
-		if (boot_cpu_has(X86_FEATURE_SEV) &&
-		    IS_ENABLED(CONFIG_KVM_AMD_SEV)) {
-			r = sev_hardware_setup();
-			if (r)
-				sev = false;
-		} else {
-			sev = false;
-		}
+	if (IS_ENABLED(CONFIG_KVM_AMD_SEV) && sev) {
+		sev_hardware_setup();
+	} else {
+		sev = false;
+		sev_es = false;
 	}
 
 	svm_adjust_mmio_mask();
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index a798e1731709..2692ddf30c8d 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -60,6 +60,7 @@  enum {
 
 struct kvm_sev_info {
 	bool active;		/* SEV enabled guest */
+	bool es_active;		/* SEV-ES enabled guest */
 	unsigned int asid;	/* ASID used for this guest */
 	unsigned int handle;	/* SEV firmware handle */
 	int fd;			/* SEV device fd */
@@ -348,6 +349,9 @@  static inline bool gif_set(struct vcpu_svm *svm)
 #define MSR_CR3_LONG_RESERVED_MASK		0xfff0000000000fe7U
 #define MSR_INVALID				0xffffffffU
 
+extern int sev;
+extern int sev_es;
+
 u32 svm_msrpm_offset(u32 msr);
 void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer);
 void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
@@ -474,6 +478,17 @@  static inline bool sev_guest(struct kvm *kvm)
 #endif
 }
 
+static inline bool sev_es_guest(struct kvm *kvm)
+{
+#ifdef CONFIG_KVM_AMD_SEV
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+
+	return sev_guest(kvm) && sev->es_active;
+#else
+	return false;
+#endif
+}
+
 static inline bool svm_sev_enabled(void)
 {
 	return IS_ENABLED(CONFIG_KVM_AMD_SEV) ? max_sev_asid : 0;
@@ -486,7 +501,7 @@  int svm_register_enc_region(struct kvm *kvm,
 int svm_unregister_enc_region(struct kvm *kvm,
 			      struct kvm_enc_region *range);
 void pre_sev_run(struct vcpu_svm *svm, int cpu);
-int __init sev_hardware_setup(void);
+void __init sev_hardware_setup(void);
 void sev_hardware_teardown(void);
 
 #endif