diff options
Diffstat (limited to 'system/xen/xsa/xsa263-4.10-0001-x86-spec_ctrl-Read-MSR_ARCH_CAPABILITIES-only-once.patch')
-rw-r--r-- | system/xen/xsa/xsa263-4.10-0001-x86-spec_ctrl-Read-MSR_ARCH_CAPABILITIES-only-once.patch | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/system/xen/xsa/xsa263-4.10-0001-x86-spec_ctrl-Read-MSR_ARCH_CAPABILITIES-only-once.patch b/system/xen/xsa/xsa263-4.10-0001-x86-spec_ctrl-Read-MSR_ARCH_CAPABILITIES-only-once.patch new file mode 100644 index 0000000000..c26afebc20 --- /dev/null +++ b/system/xen/xsa/xsa263-4.10-0001-x86-spec_ctrl-Read-MSR_ARCH_CAPABILITIES-only-once.patch @@ -0,0 +1,110 @@ +From 13fafdf5c97d3bc2a8851c4d1796feac0f82d498 Mon Sep 17 00:00:00 2001 +From: Andrew Cooper <andrew.cooper3@citrix.com> +Date: Thu, 26 Apr 2018 12:21:00 +0100 +Subject: [PATCH] x86/spec_ctrl: Read MSR_ARCH_CAPABILITIES only once + +Make it available from the beginning of init_speculation_mitigations(), and +pass it into appropriate functions. Fix an RSBA typo while moving the +affected comment. + +Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> +Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> +Reviewed-by: Wei Liu <wei.liu2@citrix.com> +Reviewed-by: Jan Beulich <jbeulich@suse.com> +Release-acked-by: Juergen Gross <jgross@suse.com> +(cherry picked from commit d6c65187252a6c1810fd24c4d46f812840de8d3c) +--- + xen/arch/x86/spec_ctrl.c | 34 ++++++++++++++-------------------- + 1 file changed, 14 insertions(+), 20 deletions(-) + +diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c +index fa67a0f..dc90743 100644 +--- a/xen/arch/x86/spec_ctrl.c ++++ b/xen/arch/x86/spec_ctrl.c +@@ -81,18 +81,15 @@ static int __init parse_bti(const char *s) + } + custom_param("bti", parse_bti); + +-static void __init print_details(enum ind_thunk thunk) ++static void __init print_details(enum ind_thunk thunk, uint64_t caps) + { + unsigned int _7d0 = 0, e8b = 0, tmp; +- uint64_t caps = 0; + + /* Collect diagnostics about available mitigations. */ + if ( boot_cpu_data.cpuid_level >= 7 ) + cpuid_count(7, 0, &tmp, &tmp, &tmp, &_7d0); + if ( boot_cpu_data.extended_cpuid_level >= 0x80000008 ) + cpuid(0x80000008, &tmp, &e8b, &tmp, &tmp); +- if ( _7d0 & cpufeat_mask(X86_FEATURE_ARCH_CAPS) ) +- rdmsrl(MSR_ARCH_CAPABILITIES, caps); + + printk(XENLOG_DEBUG "Speculative mitigation facilities:\n"); + +@@ -125,7 +122,7 @@ static void __init print_details(enum ind_thunk thunk) + } + + /* Calculate whether Retpoline is known-safe on this CPU. */ +-static bool __init retpoline_safe(void) ++static bool __init retpoline_safe(uint64_t caps) + { + unsigned int ucode_rev = this_cpu(ucode_cpu_info).cpu_sig.rev; + +@@ -136,19 +133,12 @@ static bool __init retpoline_safe(void) + boot_cpu_data.x86 != 6 ) + return false; + +- if ( boot_cpu_has(X86_FEATURE_ARCH_CAPS) ) +- { +- uint64_t caps; +- +- rdmsrl(MSR_ARCH_CAPABILITIES, caps); +- +- /* +- * RBSA may be set by a hypervisor to indicate that we may move to a +- * processor which isn't retpoline-safe. +- */ +- if ( caps & ARCH_CAPS_RSBA ) +- return false; +- } ++ /* ++ * RSBA may be set by a hypervisor to indicate that we may move to a ++ * processor which isn't retpoline-safe. ++ */ ++ if ( caps & ARCH_CAPS_RSBA ) ++ return false; + + switch ( boot_cpu_data.x86_model ) + { +@@ -218,6 +208,10 @@ void __init init_speculation_mitigations(void) + { + enum ind_thunk thunk = THUNK_DEFAULT; + bool ibrs = false; ++ uint64_t caps = 0; ++ ++ if ( boot_cpu_has(X86_FEATURE_ARCH_CAPS) ) ++ rdmsrl(MSR_ARCH_CAPABILITIES, caps); + + /* + * Has the user specified any custom BTI mitigations? If so, follow their +@@ -246,7 +240,7 @@ void __init init_speculation_mitigations(void) + * On Intel hardware, we'd like to use retpoline in preference to + * IBRS, but only if it is safe on this hardware. + */ +- else if ( retpoline_safe() ) ++ else if ( retpoline_safe(caps) ) + thunk = THUNK_RETPOLINE; + else if ( boot_cpu_has(X86_FEATURE_IBRSB) ) + ibrs = true; +@@ -331,7 +325,7 @@ void __init init_speculation_mitigations(void) + /* (Re)init BSP state now that default_bti_ist_info has been calculated. */ + init_shadow_spec_ctrl_state(); + +- print_details(thunk); ++ print_details(thunk, caps); + } + + static void __init __maybe_unused build_assertions(void) +-- +2.1.4 + |