From 62a08a7193dc9107904aaa51a04ba3ba2959f745 Mon Sep 17 00:00:00 2001 From: Tom Lendacky <thomas.lendacky@amd.com> Date: Mon, 1 Feb 2021 12:26:27 -0600 Subject: [PATCH] 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 c79e5736ab2b7e..d55ea77e1ca8dd 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(); -- GitLab