From 606b21d4a6498c23632a4693c81b7b24feedd038 Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Fri, 20 Oct 2017 09:30:55 -0500 Subject: x86/io: Unroll string I/O when SEV is active Secure Encrypted Virtualization (SEV) does not support string I/O, so unroll the string I/O operation into a loop operating on one element at a time. [ tglx: Gave the static key a real name instead of the obscure __sev ] Signed-off-by: Tom Lendacky Signed-off-by: Brijesh Singh Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Tested-by: Borislav Petkov Cc: Andy Shevchenko Cc: Arnd Bergmann Cc: kvm@vger.kernel.org Cc: David Laight Cc: Borislav Petkov Link: https://lkml.kernel.org/r/20171020143059.3291-14-brijesh.singh@amd.com --- arch/x86/mm/mem_encrypt.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'arch/x86/mm') diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c index fd9c7bb51664..d29b7831a053 100644 --- a/arch/x86/mm/mem_encrypt.c +++ b/arch/x86/mm/mem_encrypt.c @@ -41,6 +41,8 @@ static char sme_cmdline_off[] __initdata = "off"; */ u64 sme_me_mask __section(.data) = 0; EXPORT_SYMBOL_GPL(sme_me_mask); +DEFINE_STATIC_KEY_FALSE(sev_enable_key); +EXPORT_SYMBOL_GPL(sev_enable_key); static bool sev_enabled __section(.data); @@ -313,6 +315,12 @@ void __init mem_encrypt_init(void) if (sev_active()) dma_ops = &sev_dma_ops; + /* + * With SEV, we need to unroll the rep string I/O instructions. + */ + if (sev_active()) + static_branch_enable(&sev_enable_key); + pr_info("AMD %s active\n", sev_active() ? "Secure Encrypted Virtualization (SEV)" : "Secure Memory Encryption (SME)"); -- cgit v1.2.3