From 73924ec4d560257004d5b5116b22a3647661e364 Mon Sep 17 00:00:00 2001 From: Pawan Gupta Date: Mon, 4 Apr 2022 17:34:19 -0700 Subject: x86/pm: Save the MSR validity status at context setup The mechanism to save/restore MSRs during S3 suspend/resume checks for the MSR validity during suspend, and only restores the MSR if its a valid MSR. This is not optimal, as an invalid MSR will unnecessarily throw an exception for every suspend cycle. The more invalid MSRs, higher the impact will be. Check and save the MSR validity at setup. This ensures that only valid MSRs that are guaranteed to not throw an exception will be attempted during suspend. Fixes: 7a9c2dd08ead ("x86/pm: Introduce quirk framework to save/restore extra MSR registers around suspend/resume") Suggested-by: Dave Hansen Signed-off-by: Pawan Gupta Reviewed-by: Dave Hansen Acked-by: Borislav Petkov Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds --- arch/x86/power/cpu.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 9f2b251e83c5..eaec0cb3fe04 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -40,7 +40,8 @@ static void msr_save_context(struct saved_context *ctxt) struct saved_msr *end = msr + ctxt->saved_msrs.num; while (msr < end) { - msr->valid = !rdmsrl_safe(msr->info.msr_no, &msr->info.reg.q); + if (msr->valid) + rdmsrl(msr->info.msr_no, msr->info.reg.q); msr++; } } @@ -424,8 +425,10 @@ static int msr_build_context(const u32 *msr_id, const int num) } for (i = saved_msrs->num, j = 0; i < total_num; i++, j++) { + u64 dummy; + msr_array[i].info.msr_no = msr_id[j]; - msr_array[i].valid = false; + msr_array[i].valid = !rdmsrl_safe(msr_id[j], &dummy); msr_array[i].info.reg.q = 0; } saved_msrs->num = total_num; -- cgit v1.2.3 From e2a1256b17b16f9b9adf1b6fea56819e7b68e463 Mon Sep 17 00:00:00 2001 From: Pawan Gupta Date: Mon, 4 Apr 2022 17:35:45 -0700 Subject: x86/speculation: Restore speculation related MSRs during S3 resume After resuming from suspend-to-RAM, the MSRs that control CPU's speculative execution behavior are not being restored on the boot CPU. These MSRs are used to mitigate speculative execution vulnerabilities. Not restoring them correctly may leave the CPU vulnerable. Secondary CPU's MSRs are correctly being restored at S3 resume by identify_secondary_cpu(). During S3 resume, restore these MSRs for boot CPU when restoring its processor state. Fixes: 772439717dbf ("x86/bugs/intel: Set proper CPU features and setup RDS") Reported-by: Neelima Krishnan Signed-off-by: Pawan Gupta Tested-by: Neelima Krishnan Acked-by: Borislav Petkov Reviewed-by: Dave Hansen Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds --- arch/x86/power/cpu.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'arch') diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index eaec0cb3fe04..3822666fb73d 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -503,10 +503,24 @@ static int pm_cpu_check(const struct x86_cpu_id *c) return ret; } +static void pm_save_spec_msr(void) +{ + u32 spec_msr_id[] = { + MSR_IA32_SPEC_CTRL, + MSR_IA32_TSX_CTRL, + MSR_TSX_FORCE_ABORT, + MSR_IA32_MCU_OPT_CTRL, + MSR_AMD64_LS_CFG, + }; + + msr_build_context(spec_msr_id, ARRAY_SIZE(spec_msr_id)); +} + static int pm_check_save_msr(void) { dmi_check_system(msr_save_dmi_table); pm_cpu_check(msr_save_cpu_table); + pm_save_spec_msr(); return 0; } -- cgit v1.2.3