[PATCH v7 10/18] x86/paravirt: Add hypervisor specific hypercall for SEV live migration.

[Ashish Kalra <Ashish.Kalra@amd.com>]

From: Ashish Kalra <ashish.kalra@amd.com>

Add a new paravirt callback as part of x86_hyper_runtime
(x86 hypervisor specific runtime callbacks) to do hypervisor
specific page encryption status notifications from the SEV
guest.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 arch/x86/include/asm/x86_init.h | 10 +++++++++-
 arch/x86/kernel/kvm.c           | 12 ++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 96d9cd208610..888dca30a17a 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -238,10 +238,18 @@ struct x86_legacy_features {
 /**
  * struct x86_hyper_runtime - x86 hypervisor specific runtime callbacks
  *
- * @pin_vcpu:		pin current vcpu to specified physical cpu (run rarely)
+ * @pin_vcpu:			pin current vcpu to specified physical
+ * 				cpu (run rarely)
+ * @sev_migration_hcall:	this hypercall is used by the SEV guest
+ * 				to notify a change in the page encryption
+ * 				status to the hypervisor.
  */
 struct x86_hyper_runtime {
 	void (*pin_vcpu)(int cpu);
+#if defined(CONFIG_AMD_MEM_ENCRYPT)
+	long (*sev_migration_hcall)(unsigned long physaddr,
+				    unsigned long npages, bool enc);
+#endif
 };
 
 /**
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 6efe0410fb72..928ddb8a8cfc 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -729,6 +729,15 @@ static void __init kvm_init_platform(void)
 	x86_platform.apic_post_init = kvm_apic_init;
 }
 
+#if defined(CONFIG_AMD_MEM_ENCRYPT)
+long kvm_sev_migration_hcall(unsigned long physaddr, unsigned long npages,
+			     bool enc)
+{
+	return kvm_sev_hypercall3(KVM_HC_PAGE_ENC_STATUS, physaddr, npages,
+				  enc);
+}
+#endif
+
 const __initconst struct hypervisor_x86 x86_hyper_kvm = {
 	.name			= "KVM",
 	.detect			= kvm_detect,
@@ -736,6 +745,9 @@ const __initconst struct hypervisor_x86 x86_hyper_kvm = {
 	.init.guest_late_init	= kvm_guest_init,
 	.init.x2apic_available	= kvm_para_available,
 	.init.init_platform	= kvm_init_platform,
+#if defined(CONFIG_AMD_MEM_ENCRYPT)
+	.runtime.sev_migration_hcall = kvm_sev_migration_hcall,
+#endif
 };
 
 static __init int activate_jump_labels(void)
-- 
2.17.1