[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.16] x86/boot: Adjust MSR_ARCH_CAPS handling for the Host policy
commit a21bfbd10b0daf46bd596b7bde2d0a6a9351ffa7 Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> AuthorDate: Mon May 15 14:14:53 2023 +0100 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Tue Aug 8 16:02:53 2023 +0100 x86/boot: Adjust MSR_ARCH_CAPS handling for the Host policy We are about to move MSR_ARCH_CAPS into featureset, but the order of operations (copy raw policy, then copy x86_capabilitiles[] in) will end up clobbering the ARCH_CAPS value. Some toolstacks use this information to handle TSX compatibility across the CPUs and microcode versions where support was removed. To avoid this transient breakage, read from raw_cpu_policy rather than modifying it in place. This logic will be removed entirely in due course. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Acked-by: Jan Beulich <jbeulich@xxxxxxxx> (cherry picked from commit 43912f8dbb1888ffd7f00adb10724c70e71927c4) --- xen/arch/x86/cpu-policy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/xen/arch/x86/cpu-policy.c b/xen/arch/x86/cpu-policy.c index 351973a866..b650af431c 100644 --- a/xen/arch/x86/cpu-policy.c +++ b/xen/arch/x86/cpu-policy.c @@ -411,7 +411,7 @@ static void __init calculate_host_policy(void) p->platform_info.cpuid_faulting = cpu_has_cpuid_faulting; /* Temporary, until we have known_features[] for feature bits in MSRs. */ - p->arch_caps.raw &= + p->arch_caps.raw = raw_cpu_policy.arch_caps.raw & (ARCH_CAPS_RDCL_NO | ARCH_CAPS_IBRS_ALL | ARCH_CAPS_RSBA | ARCH_CAPS_SKIP_L1DFL | ARCH_CAPS_SSB_NO | ARCH_CAPS_MDS_NO | ARCH_CAPS_IF_PSCHANGE_MC_NO | ARCH_CAPS_TSX_CTRL | ARCH_CAPS_TAA_NO | -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.16
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