linux-kernel - [RFC PATCH v1 14/28] x86: Don't set the SME MSR bit when SEV is active

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Date:   Mon, 22 Aug 2016 19:26:28 -0400
From:   Brijesh Singh <brijesh.singh@....com>
To:     <simon.guinot@...uanux.org>, <linux-efi@...r.kernel.org>,
        <brijesh.singh@....com>, <kvm@...r.kernel.org>,
        <rkrcmar@...hat.com>, <matt@...eblueprint.co.uk>,
        <linus.walleij@...aro.org>, <linux-mm@...ck.org>,
        <paul.gortmaker@...driver.com>, <hpa@...or.com>,
        <dan.j.williams@...el.com>, <aarcange@...hat.com>,
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        <xemul@...allels.com>, <joro@...tes.org>, <x86@...nel.org>,
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        <thomas.lendacky@....com>, <jroedel@...e.de>,
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        <davem@...emloft.net>
Subject: [RFC PATCH v1 14/28] x86: Don't set the SME MSR bit when SEV is
 active

From: Tom Lendacky <thomas.lendacky@....com>

When SEV is active the virtual machine cannot set the MSR for SME, so
don't set the trampoline flag for SME.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
 arch/x86/realmode/init.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index f3207e5..391d8ba 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -102,7 +102,7 @@ static void __init setup_real_mode(void)
 	*trampoline_cr4_features = mmu_cr4_features;
 
 	trampoline_header->flags = 0;
-	if (sme_me_mask)
+	if (sme_me_mask && !sev_active)
 		trampoline_header->flags |= TH_FLAGS_SME_ENABLE;
 
 	trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);