| From | "Huang, Kai" <> | Subject | Re: [PATCH v10 035/108] KVM: x86/mmu: Track shadow MMIO value on a per-VM basis | Date | Wed, 9 Nov 2022 12:27:33 +0000 |
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On Sat, 2022-10-29 at 23:22 -0700, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > TDX will use a different shadow PTE entry value for MMIO from VMX. Add > members to kvm_arch and track value for MMIO per-VM instead of global > variables. By using the per-VM EPT entry value for MMIO, the existing VMX > logic is kept working. To untangle the logic to initialize > shadow_mmio_access_mask, introduce a separate setter function. >
It's weird to mention "shadow_mmio_access_mask" here (and this doesn't stand anymore anyway as we have changed to only make mmio_value per-vm). Just say something like "introduce a setter function to set mmio_value for the given guest so that TDX guest can override later".
Also, seems it's worth to mention the same mmio_mask is used for both TDX guest and VMX guest so we can still use global shadow_mmio_mask.
[...]
> void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask) > { > BUG_ON((u64)(unsigned)access_mask != access_mask); > + > WARN_ON(mmio_value & shadow_nonpresent_or_rsvd_lower_gfn_mask);
Looks unnecessary change.
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