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85c17291e2
Add a new feature flag, X86_FEATURE_MSR_IA32_FEAT_CTL, to track whether IA32_FEAT_CTL has been initialized. This will allow KVM, and any future subsystems that depend on IA32_FEAT_CTL, to rely purely on cpufeatures to query platform support, e.g. allows a future patch to remove KVM's manual IA32_FEAT_CTL MSR checks. Various features (on platforms that support IA32_FEAT_CTL) are dependent on IA32_FEAT_CTL being configured and locked, e.g. VMX and LMCE. The MSR is always configured during boot, but only if the CPU vendor is recognized by the kernel. Because CPUID doesn't incorporate the current IA32_FEAT_CTL value in its reporting of relevant features, it's possible for a feature to be reported as supported in cpufeatures but not truly enabled, e.g. if the CPU supports VMX but the kernel doesn't recognize the CPU. As a result, without the flag, KVM would see VMX as supported even if IA32_FEAT_CTL hasn't been initialized, and so would need to manually read the MSR and check the various enabling bits to avoid taking an unexpected #GP on VMXON. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20191221044513.21680-14-sean.j.christopherson@intel.com |
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| .. | ||
| boot | ||
| configs | ||
| crypto | ||
| entry | ||
| events | ||
| hyperv | ||
| ia32 | ||
| include | ||
| kernel | ||
| kvm | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| oprofile | ||
| pci | ||
| platform | ||
| power | ||
| purgatory | ||
| ras | ||
| realmode | ||
| tools | ||
| um | ||
| video | ||
| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile.um | ||
| Makefile_32.cpu | ||