From: Stefan Fritsch <sf@sfritsch.de>
Subject: Re: SEV-ES multiprocessor support / handle WBINDV
To: tech@openbsd.org
Cc: Mike Larkin <mlarkin@nested.page>
Date: Tue, 25 Nov 2025 10:41:45 +0100

Hi,

On Thu, 18 Sep 2025, Stefan Fritsch wrote:
> one remaining problem with SEV-ES is that we don't support multiprocessor 

for multiprocessor support with SEV-ES, we need to handle WBINDV in the
VC trap handler.

This is the the first part of the larger diff that I have sent in the
mail quoted above.

ok?

Cheers,
Stefan


diff --git a/sys/arch/amd64/amd64/trap.c b/sys/arch/amd64/amd64/trap.c
index 0feb17cbdee..d953e6b54f5 100644
--- a/sys/arch/amd64/amd64/trap.c
+++ b/sys/arch/amd64/amd64/trap.c
@@ -445,6 +445,16 @@ vctrap(struct trapframe *frame, int user, int *sig, int *code)
 		}
 		panic("unexpected MMIO in kernelspace");
 		/* NOTREACHED */
+	case SVM_VMEXIT_WBINVD:
+		/*
+		 * There is no special GHCB request for WBNOINVD.
+		 * Signal WBINVD to emulate WBNOINVD.
+		 */
+		if (*rip == 0xf3)
+			frame->tf_rip += 3;
+		else
+			frame->tf_rip += 2;
+		break;
 	default:
 		panic("invalid exit code 0x%llx", ghcb_regs.exitcode);
 	}
-- 
2.39.5