[PATCH v4 59/75] x86/sev-es: Handle MONITOR/MONITORX Events

Joerg Roedel
Tue, 14 Jul 2020 12:09:01 -0000

From: Tom Lendacky <thomas.lendacky at amd.com>

Implement a handler for #VC exceptions caused by MONITOR and MONITORX
instructions.

Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
[ jroedel at suse.de: Adapt to #VC handling infrastructure ]
Co-developed-by: Joerg Roedel <jroedel at suse.de>
Signed-off-by: Joerg Roedel <jroedel at suse.de>
---
 arch/x86/kernel/sev-es.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 30d6161deada..c0977bdc400e 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -878,6 +878,16 @@ static enum es_result vc_handle_rdpmc(struct ghcb *ghcb,
struct es_em_ctxt *ctxt
 	return ES_OK;
 }

+static enum es_result vc_handle_monitor(struct ghcb *ghcb,
+					struct es_em_ctxt *ctxt)
+{
+	/*
+	 * Treat it as a NOP and do not leak a physical address to the
+	 * hypervisor
+	 */
+	return ES_OK;
+}
+
 static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
 					 struct ghcb *ghcb,
 					 unsigned long exit_code)
@@ -914,6 +924,9 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt
*ctxt,
 	case SVM_EXIT_WBINVD:
 		result = vc_handle_wbinvd(ghcb, ctxt);
 		break;
+	case SVM_EXIT_MONITOR:
+		result = vc_handle_monitor(ghcb, ctxt);
+		break;
 	case SVM_EXIT_NPF:
 		result = vc_handle_mmio(ghcb, ctxt);
 		break;
--
2.27.0