On Tue, 19 Mar 2024 11:11:11 +0800, Tao Su wrote:
> Intel MKTME repurposes several high bits of physical address as 'keyID',
> so boot_cpu_data.x86_phys_bits doesn't hold physical address bits reported
> by CPUID anymore.
>
> If guest.MAXPHYADDR < host.MAXPHYADDR, the bit field of ‘keyID’ belongs
> to reserved bits in guest’s view, so intercepting #PF to fix error code
> is necessary, just replace boot_cpu_data.x86_phys_bits with
> kvm_get_shadow_phys_bits() to fix.
>
> [...]
Applied to kvm-x86 fixes, with a massaged shortlog/changelog.
Note, I don't love using kvm_get_shadow_phys_bits(), but only because doing
CPUID every time is so pointlessly suboptimal. I have a series to clean up all
of the related code, which I'll hopefully post later this week.
But I didn't see any reason to hold up this fix, as I really hope no one is
using allow_smaller_maxphyaddr in a nested VM with EPT enabled, which is the
only case where CPUID is likely to have a meaningful impact (due to causing a
VM-Exit).
[1/1] KVM: x86: Fix the condition of #PF interception caused by MKTME
https://github.com/kvm-x86/linux/commit/7f2817ef52a1
--
https://github.com/kvm-x86/linux/tree/next
