[PATCH v6 66/76] x86/kvm: Add KVM specific VMMCALL handling under SEV-ES

[Joerg Roedel]

From: Tom Lendacky <thomas.lendacky@xxxxxxx>

Implement the callbacks to copy the processor state required by KVM to
the GHCB.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
[ jroedel@xxxxxxx: - Split out of a larger patch
                   - Adapt to different callback functions ]
Co-developed-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Link: https://lore.kernel.org/r/20200724160336.5435-66-joro@xxxxxxxxxx
---
 arch/x86/kernel/kvm.c | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 08320b0b2b27..0f9597275e9c 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -36,6 +36,8 @@
 #include <asm/hypervisor.h>
 #include <asm/tlb.h>
 #include <asm/cpuidle_haltpoll.h>
+#include <asm/ptrace.h>
+#include <asm/svm.h>
 
 DEFINE_STATIC_KEY_FALSE(kvm_async_pf_enabled);
 
@@ -746,13 +748,34 @@ static void __init kvm_init_platform(void)
 	x86_platform.apic_post_init = kvm_apic_init;
 }
 
+#if defined(CONFIG_AMD_MEM_ENCRYPT)
+static void kvm_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
+{
+	/* RAX and CPL are already in the GHCB */
+	ghcb_set_rbx(ghcb, regs->bx);
+	ghcb_set_rcx(ghcb, regs->cx);
+	ghcb_set_rdx(ghcb, regs->dx);
+	ghcb_set_rsi(ghcb, regs->si);
+}
+
+static bool kvm_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
+{
+	/* No checking of the return state needed */
+	return true;
+}
+#endif
+
 const __initconst struct hypervisor_x86 x86_hyper_kvm = {
-	.name			= "KVM",
-	.detect			= kvm_detect,
-	.type			= X86_HYPER_KVM,
-	.init.guest_late_init	= kvm_guest_init,
-	.init.x2apic_available	= kvm_para_available,
-	.init.init_platform	= kvm_init_platform,
+	.name				= "KVM",
+	.detect				= kvm_detect,
+	.type				= 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_es_hcall_prepare	= kvm_sev_es_hcall_prepare,
+	.runtime.sev_es_hcall_finish	= kvm_sev_es_hcall_finish,
+#endif
 };
 
 static __init int activate_jump_labels(void)
-- 
2.28.0