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52887af565
Revert the recently added virtualizing of MSR_IA32_FLUSH_CMD, as both the VMX and SVM are fatally buggy to guests that use MSR_IA32_FLUSH_CMD or MSR_IA32_PRED_CMD, and because the entire foundation of the logic is flawed. The most immediate problem is an inverted check on @cmd that results in rejecting legal values. SVM doubles down on bugs and drops the error, i.e. silently breaks all guest mitigations based on the command MSRs. The next issue is that neither VMX nor SVM was updated to mark MSR_IA32_FLUSH_CMD as being a possible passthrough MSR, which isn't hugely problematic, but does break MSR filtering and triggers a WARN on VMX designed to catch this exact bug. The foundational issues stem from the MSR_IA32_FLUSH_CMD code reusing logic from MSR_IA32_PRED_CMD, which in turn was likely copied from KVM's support for MSR_IA32_SPEC_CTRL. The copy+paste from MSR_IA32_SPEC_CTRL was misguided as MSR_IA32_PRED_CMD (and MSR_IA32_FLUSH_CMD) is a write-only MSR, i.e. doesn't need the same "deferred passthrough" shenanigans as MSR_IA32_SPEC_CTRL. Revert all MSR_IA32_FLUSH_CMD enabling in one fell swoop so that there is no point where KVM advertises, but does not support, L1D_FLUSH. This reverts commits |
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| .. | ||
| boot | ||
| coco | ||
| configs | ||
| crypto | ||
| entry | ||
| events | ||
| hyperv | ||
| ia32 | ||
| include | ||
| kernel | ||
| kvm | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| pci | ||
| platform | ||
| power | ||
| purgatory | ||
| ras | ||
| realmode | ||
| tools | ||
| um | ||
| video | ||
| virt/vmx/tdx | ||
| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.assembler | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile_32.cpu | ||
| Makefile.um | ||