diff mbox series

[v9,13/18] KVM: x86: Introduce new KVM_FEATURE_SEV_LIVE_MIGRATION feature & Custom MSR.

Message ID a67e0a02e8922e13d766c128708f5948fbda3a26.1607460588.git.ashish.kalra@amd.com (mailing list archive)
State New, archived
Headers show
Series Add AMD SEV guest live migration support | expand

Commit Message

Kalra, Ashish Dec. 8, 2020, 10:07 p.m. UTC 
From: Ashish Kalra <ashish.kalra@amd.com>

Add new KVM_FEATURE_SEV_LIVE_MIGRATION feature for guest to check
for host-side support for SEV live migration. Also add a new custom
MSR_KVM_SEV_LIVE_MIG_EN for guest to enable the SEV live migration
feature.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 Documentation/virt/kvm/cpuid.rst     |  5 +++++
 Documentation/virt/kvm/msr.rst       | 16 ++++++++++++++++
 arch/x86/include/uapi/asm/kvm_para.h |  5 +++++
 arch/x86/kvm/svm/sev.c               | 14 ++++++++++++++
 arch/x86/kvm/svm/svm.c               | 16 ++++++++++++++++
 arch/x86/kvm/svm/svm.h               |  2 ++
 6 files changed, 58 insertions(+)
diff mbox series

Patch

diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst
index cf62162d4be2..0bdb6cdb12d3 100644
--- a/Documentation/virt/kvm/cpuid.rst
+++ b/Documentation/virt/kvm/cpuid.rst
@@ -96,6 +96,11 @@  KVM_FEATURE_MSI_EXT_DEST_ID        15          guest checks this feature bit
                                                before using extended destination
                                                ID bits in MSI address bits 11-5.
 
+KVM_FEATURE_SEV_LIVE_MIGRATION     16          guest checks this feature bit before
+                                               using the page encryption state
+                                               hypercall to notify the page state
+                                               change
+
 KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24          host will warn if no guest-side
                                                per-cpu warps are expected in
                                                kvmclock
diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst
index e37a14c323d2..ffac027aba5b 100644
--- a/Documentation/virt/kvm/msr.rst
+++ b/Documentation/virt/kvm/msr.rst
@@ -376,3 +376,19 @@  data:
 	write '1' to bit 0 of the MSR, this causes the host to re-scan its queue
 	and check if there are more notifications pending. The MSR is available
 	if KVM_FEATURE_ASYNC_PF_INT is present in CPUID.
+
+MSR_KVM_SEV_LIVE_MIG_EN:
+        0x4b564d08
+
+	Control SEV Live Migration features.
+
+data:
+        Bit 0 enables (1) or disables (0) host-side SEV Live Migration feature,
+        in other words, this is guest->host communication that it's properly
+        handling the encryption bitmap.
+
+        Bit 1 enables (1) or disables (0) support for SEV Live Migration extensions,
+        any future extensions related to this live migration support, such as
+        extensions/support for accelerated migration, etc.
+
+        All other bits are reserved.
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 950afebfba88..0e8e59115ce2 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -33,6 +33,7 @@ 
 #define KVM_FEATURE_PV_SCHED_YIELD	13
 #define KVM_FEATURE_ASYNC_PF_INT	14
 #define KVM_FEATURE_MSI_EXT_DEST_ID	15
+#define KVM_FEATURE_SEV_LIVE_MIGRATION	16
 
 #define KVM_HINTS_REALTIME      0
 
@@ -54,6 +55,7 @@ 
 #define MSR_KVM_POLL_CONTROL	0x4b564d05
 #define MSR_KVM_ASYNC_PF_INT	0x4b564d06
 #define MSR_KVM_ASYNC_PF_ACK	0x4b564d07
+#define MSR_KVM_SEV_LIVE_MIG_EN	0x4b564d08
 
 struct kvm_steal_time {
 	__u64 steal;
@@ -136,4 +138,7 @@  struct kvm_vcpu_pv_apf_data {
 #define KVM_PV_EOI_ENABLED KVM_PV_EOI_MASK
 #define KVM_PV_EOI_DISABLED 0x0
 
+#define KVM_SEV_LIVE_MIGRATION_ENABLED			(1 << 0)
+#define KVM_SEV_LIVE_MIGRATION_EXTENSIONS_SUPPORTED	(1 << 1)
+
 #endif /* _UAPI_ASM_X86_KVM_PARA_H */
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index b87b6225d2da..83565e35fa09 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1483,6 +1483,17 @@  int svm_page_enc_status_hc(struct kvm *kvm, unsigned long gpa,
 	return 0;
 }
 
+void sev_update_migration_flags(struct kvm *kvm, u64 data)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+
+	if (!sev_guest(kvm))
+		return;
+
+	if (data & KVM_SEV_LIVE_MIGRATION_ENABLED)
+		sev->live_migration_enabled = true;
+}
+
 int svm_get_page_enc_bitmap(struct kvm *kvm,
 				   struct kvm_page_enc_bitmap *bmap)
 {
@@ -1495,6 +1506,9 @@  int svm_get_page_enc_bitmap(struct kvm *kvm,
 	if (!sev_guest(kvm))
 		return -ENOTTY;
 
+	if (!sev->live_migration_enabled)
+		return -EINVAL;
+
 	gfn_start = bmap->start_gfn;
 	gfn_end = gfn_start + bmap->num_pages;
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 7aa7858c8209..6f47db7b8805 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2765,6 +2765,9 @@  static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 		svm->msr_decfg = data;
 		break;
 	}
+	case MSR_KVM_SEV_LIVE_MIG_EN:
+		sev_update_migration_flags(vcpu->kvm, data);
+		break;
 	case MSR_IA32_APICBASE:
 		if (kvm_vcpu_apicv_active(vcpu))
 			avic_update_vapic_bar(to_svm(vcpu), data);
@@ -3769,6 +3772,19 @@  static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 			vcpu->arch.cr3_lm_rsvd_bits &= ~(1UL << (best->ebx & 0x3f));
 	}
 
+        /*
+         * If SEV guest then enable the Live migration feature.
+         */
+        if (sev_guest(vcpu->kvm)) {
+              struct kvm_cpuid_entry2 *best;
+
+              best = kvm_find_cpuid_entry(vcpu, KVM_CPUID_FEATURES, 0);
+              if (!best)
+                      return;
+
+              best->eax |= (1 << KVM_FEATURE_SEV_LIVE_MIGRATION);
+        }
+
 	if (!kvm_vcpu_apicv_active(vcpu))
 		return;
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 5a4656bad681..d1f503dc2584 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -66,6 +66,7 @@  struct kvm_sev_info {
 	int fd;			/* SEV device fd */
 	unsigned long pages_locked; /* Number of pages locked */
 	struct list_head regions_list;  /* List of registered regions */
+	bool live_migration_enabled;
 	unsigned long *page_enc_bmap;
 	unsigned long page_enc_bmap_size;
 };
@@ -505,5 +506,6 @@  int svm_unregister_enc_region(struct kvm *kvm,
 void pre_sev_run(struct vcpu_svm *svm, int cpu);
 int __init sev_hardware_setup(void);
 void sev_hardware_teardown(void);
+void sev_update_migration_flags(struct kvm *kvm, u64 data);
 
 #endif