[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.13] x86/cpuid: Enumeration for BTC_NO
commit 3c71016e68f2aa324c42f66cbedd9571fe89c221 Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> AuthorDate: Mon May 16 15:48:24 2022 +0100 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Tue Jul 12 16:33:19 2022 +0100 x86/cpuid: Enumeration for BTC_NO BTC_NO indicates that hardware is not succeptable to Branch Type Confusion. Zen3 CPUs don't suffer BTC. This is part of XSA-407. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> (cherry picked from commit 76cb04ad64f3ab9ae785988c40655a71dde9c319) --- tools/libxl/libxl_cpuid.c | 1 + tools/misc/xen-cpuid.c | 2 +- xen/arch/x86/cpu/amd.c | 10 ++++++++++ xen/arch/x86/spec_ctrl.c | 5 +++-- xen/include/public/arch-x86/cpufeatureset.h | 1 + 5 files changed, 16 insertions(+), 3 deletions(-) diff --git a/tools/libxl/libxl_cpuid.c b/tools/libxl/libxl_cpuid.c index 977a4377bf..11b43807e9 100644 --- a/tools/libxl/libxl_cpuid.c +++ b/tools/libxl/libxl_cpuid.c @@ -274,6 +274,7 @@ int libxl_cpuid_parse_config(libxl_cpuid_policy_list *cpuid, const char* str) {"virt-ssbd", 0x80000008, NA, CPUID_REG_EBX, 25, 1}, {"ssb-no", 0x80000008, NA, CPUID_REG_EBX, 26, 1}, {"psfd", 0x80000008, NA, CPUID_REG_EBX, 28, 1}, + {"btc-no", 0x80000008, NA, CPUID_REG_EBX, 29, 1}, {"nc", 0x80000008, NA, CPUID_REG_ECX, 0, 8}, {"apicidsize", 0x80000008, NA, CPUID_REG_ECX, 12, 4}, diff --git a/tools/misc/xen-cpuid.c b/tools/misc/xen-cpuid.c index ff167779df..52f5059d8f 100644 --- a/tools/misc/xen-cpuid.c +++ b/tools/misc/xen-cpuid.c @@ -156,7 +156,7 @@ static const char *const str_e8b[32] = [24] = "amd-ssbd", [25] = "virt-ssbd", [26] = "ssb-no", - [28] = "psfd", + [28] = "psfd", [29] = "btc-no", }; static const char *const str_7d0[32] = diff --git a/xen/arch/x86/cpu/amd.c b/xen/arch/x86/cpu/amd.c index d5dece37cd..a2041e5138 100644 --- a/xen/arch/x86/cpu/amd.c +++ b/xen/arch/x86/cpu/amd.c @@ -707,6 +707,16 @@ static void init_amd(struct cpuinfo_x86 *c) warning_add(text); } break; + + case 0x19: + /* + * Zen3 (Fam19h model < 0x10) parts are not susceptible to + * Branch Type Confusion, but predate the allocation of the + * BTC_NO bit. Fill it back in if we're not virtualised. + */ + if (!cpu_has_hypervisor && !cpu_has(c, X86_FEATURE_BTC_NO)) + __set_bit(X86_FEATURE_BTC_NO, c->x86_capability); + break; } display_cacheinfo(c); diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c index 4517339ea6..4fdc6e93ad 100644 --- a/xen/arch/x86/spec_ctrl.c +++ b/xen/arch/x86/spec_ctrl.c @@ -387,7 +387,7 @@ static void __init print_details(enum ind_thunk thunk, uint64_t caps) * Hardware read-only information, stating immunity to certain issues, or * suggestions of which mitigation to use. */ - printk(" Hardware hints:%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n", + printk(" Hardware hints:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n", (caps & ARCH_CAPS_RDCL_NO) ? " RDCL_NO" : "", (caps & ARCH_CAPS_IBRS_ALL) ? " IBRS_ALL" : "", (caps & ARCH_CAPS_RSBA) ? " RSBA" : "", @@ -402,7 +402,8 @@ static void __init print_details(enum ind_thunk thunk, uint64_t caps) (e8b & cpufeat_mask(X86_FEATURE_IBRS_ALWAYS)) ? " IBRS_ALWAYS" : "", (e8b & cpufeat_mask(X86_FEATURE_STIBP_ALWAYS)) ? " STIBP_ALWAYS" : "", (e8b & cpufeat_mask(X86_FEATURE_IBRS_FAST)) ? " IBRS_FAST" : "", - (e8b & cpufeat_mask(X86_FEATURE_IBRS_SAME_MODE)) ? " IBRS_SAME_MODE" : ""); + (e8b & cpufeat_mask(X86_FEATURE_IBRS_SAME_MODE)) ? " IBRS_SAME_MODE" : "", + (e8b & cpufeat_mask(X86_FEATURE_BTC_NO)) ? " BTC_NO" : ""); /* Hardware features which need driving to mitigate issues. */ printk(" Hardware features:%s%s%s%s%s%s%s%s%s%s%s%s\n", diff --git a/xen/include/public/arch-x86/cpufeatureset.h b/xen/include/public/arch-x86/cpufeatureset.h index 6084e0569d..44b3ba331f 100644 --- a/xen/include/public/arch-x86/cpufeatureset.h +++ b/xen/include/public/arch-x86/cpufeatureset.h @@ -258,6 +258,7 @@ XEN_CPUFEATURE(AMD_SSBD, 8*32+24) /* MSR_SPEC_CTRL.SSBD available */ XEN_CPUFEATURE(VIRT_SSBD, 8*32+25) /* MSR_VIRT_SPEC_CTRL.SSBD */ XEN_CPUFEATURE(SSB_NO, 8*32+26) /* Hardware not vulnerable to SSB */ XEN_CPUFEATURE(PSFD, 8*32+28) /* MSR_SPEC_CTRL.PSFD */ +XEN_CPUFEATURE(BTC_NO, 8*32+29) /*A Hardware not vulnerable to Branch Type Confusion */ /* Intel-defined CPU features, CPUID level 0x00000007:0.edx, word 9 */ XEN_CPUFEATURE(AVX512_4VNNIW, 9*32+ 2) /*A AVX512 Neural Network Instructions */ -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.13
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