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@xxxxxxx> AuthorDate: Mon, 01 Feb 2021 12:26:27 -06:00 Committer: Borislav Petkov <bp@xxxxxxx> 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@xxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/3de04b5b638546ac75d42ba52307fe1a922173d3.1612203987.git.thomas.lendacky@xxxxxxx --- 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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