Hi,

On Tue, Oct 01, 2024 at 10:00:32PM +1000, Jonathan Gray wrote:
> 
> ok jsg@ if the comments are changed to remove SME:
> 
> 	 * Determine AMD SME and SEV capabilities.
> 	/* AMD CPU, check for SME and SEV. */

true! updated diff below.
-----------------------------------------------------------------------
commit 06c6d1529bc4ff4fbfdf633840bd140594483a3b
Author: Hans-Joerg Hoexer <hshoexer@genua.de>
Date:   Thu Sep 12 13:08:17 2024 +0200

    kern: Enable booting with SEV on QEMU
    
    QEMU does not forward the SME feature if SEV is enabled. This removes
    the requirement for SME in the x64 boot code.
    
    From Sebastian Sturm <ssturm@genua.de>.

diff --git a/sys/arch/amd64/amd64/locore0.S b/sys/arch/amd64/amd64/locore0.S
index bc45eee7a09..2d29ffc7057 100644
--- a/sys/arch/amd64/amd64/locore0.S
+++ b/sys/arch/amd64/amd64/locore0.S
@@ -269,37 +269,33 @@ cont:
 	orl	%edx, RELOC(cpu_feature)
 
 	/*
-	 * Determine AMD SME and SEV capabilities.
+	 * Determine AMD SEV capability.
 	 */
 	movl	$RELOC(cpu_vendor),%ebp
 	cmpl $0x68747541, (%ebp)	/* "Auth" */
-	jne	.Lno_smesev
+	jne	.Lno_sev
 	cmpl $0x69746e65, 4(%ebp)	/* "enti" */
-	jne	.Lno_smesev
+	jne	.Lno_sev
 	cmpl $0x444d4163, 8(%ebp)	/* "cAMD" */
-	jne	.Lno_smesev
+	jne	.Lno_sev
 
-	/* AMD CPU, check for SME and SEV. */
+	/* AMD CPU, check for SEV. */
 	movl	$0x8000001f, %eax
 	cpuid
-	pushl	%eax
-	andl	$CPUIDEAX_SME, %eax	/* SME */
-	popl	%eax
-	jz	.Lno_smesev
 	andl	$CPUIDEAX_SEV, %eax	/* SEV */
-	jz	.Lno_smesev
+	jz	.Lno_sev
 
 	/* Are we in guest mode with SEV enabled? */
 	movl	$MSR_SEV_STATUS, %ecx
 	rdmsr
 	andl	$SEV_STAT_ENABLED, %eax
-	jz	.Lno_smesev
+	jz	.Lno_sev
 
 	/* Determine C bit position */
 	movl	%ebx, %ecx	/* %ebx from previous cpuid */
 	andl	$0x3f, %ecx
 	cmpl	$0x20, %ecx	/* must be at least bit 32 (counting from 0) */
-	jl	.Lno_smesev
+	jl	.Lno_sev
 	xorl	%eax, %eax
 	movl	%eax, RELOC(pg_crypt)
 	subl	$0x20, %ecx
@@ -338,7 +334,7 @@ cont:
 
 	movl	$0x1, RELOC(cpu_sev_guestmode)	/* we are a SEV guest */
 
-.Lno_smesev:
+.Lno_sev:
 
 	/*
 	 * Finished with old stack; load new %esp now instead of later so we

• smime.p7s (5K)