[PATCH 52/62] x86/sev-es: Handle #DB Events

[Joerg Roedel]

From: Joerg Roedel <jroedel@xxxxxxx>

Handle #VC exceptions caused by #DB exceptions in the guest. Do not
forward them to the hypervisor and handle them with do_debug() instead.

Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
 arch/x86/kernel/sev-es.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 1b873d00e38f..700f75fc13e7 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -361,6 +361,15 @@ static enum es_result handle_vmmcall(struct ghcb *ghcb,
 	return ES_OK;
 }
 
+static enum es_result handle_db_exception(struct ghcb *ghcb,
+					  struct es_em_ctxt *ctxt)
+{
+	do_debug(ctxt->regs, 0);
+
+	/* Exception event, do not advance RIP */
+	return ES_RETRY;
+}
+
 static enum es_result handle_vc_exception(struct es_em_ctxt *ctxt,
 					  struct ghcb *ghcb,
 					  unsigned long exit_code,
@@ -375,6 +384,9 @@ static enum es_result handle_vc_exception(struct es_em_ctxt *ctxt,
 	case SVM_EXIT_WRITE_DR7:
 		result = handle_dr7_write(ghcb, ctxt, early);
 		break;
+	case SVM_EXIT_EXCP_BASE + X86_TRAP_DB:
+		result = handle_db_exception(ghcb, ctxt);
+		break;
 	case SVM_EXIT_EXCP_BASE + X86_TRAP_AC:
 		do_alignment_check(ctxt->regs, 0);
 		result = ES_RETRY;
-- 
2.17.1