[PATCH 60/70] x86/sev-es: Handle #DB Events

Joerg Roedel
2020-03-19T09:16:09Z

From: Joerg Roedel <jroedel@suse.de>

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@suse.de>
---
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 f22b361f6b60..bc553aae31d2 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -752,6 +752,15 @@ static enum es_result vc_handle_vmmcall(struct ghcb *ghcb,
return ES_OK;
}

+static enum es_result vc_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 vc_handle_exitcode(struct es_em_ctxt *ctxt,
struct ghcb *ghcb,
unsigned long exit_code,
@@ -766,6 +775,9 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
case SVM_EXIT_WRITE_DR7:
result = vc_handle_dr7_write(ghcb, ctxt, early);
break;
+ case SVM_EXIT_EXCP_BASE + X86_TRAP_DB:
+ result = vc_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