[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH 0/3] Add Automatic IBRS support
Adds support for AMD's Automatic IBRS. It's a set-and-forget feature that prevents lower privileged executions from affecting speculations of higher privileged executions, so retpolines are not required. Furthermore, it clears the RSB upon VMEXIT, so we can avoid doing it if the feature is present. Patch 1 adds the relevant bit definitions for CPUID and EFER. Patch 2 Hooks up AutoIBRS to spec_ctrl. so it's used when IBRS is picked. It also tweaks the heuristics so AutoIBRS is preferred over retpolines as BTI mitigation. This is enough to protect Xen. Patch 3 exposes the feature to HVM guests. Alejandro Vallejo (3): x86: Add bit definitions for Automatic IBRS x86: Add support for AMD's Automatic IBRS x86: Expose Automatic IBRS to guests tools/libs/light/libxl_cpuid.c | 1 + tools/misc/xen-cpuid.c | 2 + xen/arch/x86/hvm/hvm.c | 3 ++ xen/arch/x86/include/asm/cpufeature.h | 1 + xen/arch/x86/include/asm/msr-index.h | 4 +- xen/arch/x86/pv/emul-priv-op.c | 4 +- xen/arch/x86/setup.c | 3 ++ xen/arch/x86/smpboot.c | 3 ++ xen/arch/x86/spec_ctrl.c | 52 +++++++++++++++------ xen/include/public/arch-x86/cpufeatureset.h | 1 + 10 files changed, 56 insertions(+), 18 deletions(-) -- 2.34.1
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