x86/sev-es: Handle RDPMC Events

Implement a handler for #VC exceptions caused by RDPMC instructions.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
[ jroedel@suse.de: Adapt to #VC handling infrastructure ]
Co-developed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-56-joro@8bytes.org

Author: tlendacky

arch/x86/kernel/sev-es.c

@@ -853,6 +853,25 @@ static enum es_result vc_handle_wbinvd(struct ghcb *ghcb,
 	return sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WBINVD, 0, 0);
 }
 
+static enum es_result vc_handle_rdpmc(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
+{
+	enum es_result ret;
+
+	ghcb_set_rcx(ghcb, ctxt->regs->cx);
+
+	ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_RDPMC, 0, 0);
+	if (ret != ES_OK)
+		return ret;
+
+	if (!(ghcb_rax_is_valid(ghcb) && ghcb_rdx_is_valid(ghcb)))
+		return ES_VMM_ERROR;
+
+	ctxt->regs->ax = ghcb->save.rax;
+	ctxt->regs->dx = ghcb->save.rdx;
+
+	return ES_OK;
+}
+
 static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
 					 struct ghcb *ghcb,
 					 unsigned long exit_code)
@@ -870,6 +889,9 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
 	case SVM_EXIT_RDTSCP:
 		result = vc_handle_rdtsc(ghcb, ctxt, exit_code);
 		break;
+	case SVM_EXIT_RDPMC:
+		result = vc_handle_rdpmc(ghcb, ctxt);
+		break;
 	case SVM_EXIT_CPUID:
 		result = vc_handle_cpuid(ghcb, ctxt);
 		break;