* [tip: x86/seves] x86/sev-es: Do not unroll string I/O for SEV-ES guests
@ 2021-02-02 15:43 tip-bot2 for Tom Lendacky
0 siblings, 0 replies; only message in thread
From: tip-bot2 for Tom Lendacky @ 2021-02-02 15:43 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Tom Lendacky, Borislav Petkov, x86, linux-kernel
The following commit has been merged into the x86/seves branch of tip:
Commit-ID: 62a08a7193dc9107904aaa51a04ba3ba2959f745
Gitweb: https://git.kernel.org/tip/62a08a7193dc9107904aaa51a04ba3ba2959f745
Author: Tom Lendacky <thomas.lendacky@amd.com>
AuthorDate: Mon, 01 Feb 2021 12:26:27 -06:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 02 Feb 2021 16:25:05 +01:00
x86/sev-es: Do not unroll string I/O for SEV-ES guests
Under the GHCB specification, SEV-ES guests can support string I/O.
The current #VC handler contains this support, so remove the need to
unroll kernel string I/O operations. This will reduce the number of #VC
exceptions generated as well as the number VM exits for the guest.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/3de04b5b638546ac75d42ba52307fe1a922173d3.1612203987.git.thomas.lendacky@amd.com
---
arch/x86/mm/mem_encrypt.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index c79e573..d55ea77 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -474,9 +474,10 @@ void __init mem_encrypt_init(void)
swiotlb_update_mem_attributes();
/*
- * With SEV, we need to unroll the rep string I/O instructions.
+ * With SEV, we need to unroll the rep string I/O instructions,
+ * but SEV-ES supports them through the #VC handler.
*/
- if (sev_active())
+ if (sev_active() && !sev_es_active())
static_branch_enable(&sev_enable_key);
print_mem_encrypt_feature_info();
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