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SubjectRe: [PATCH v3 0/7] KVM: Guest Memory Pre-Population API
Date
On Wed, 2024-04-17 at 11:34 -0400, Paolo Bonzini wrote:
>
> Compared to Isaku's v2, I have reduced the scope as much as possible:
>
> - no vendor-specific hooks

The TDX patches build on this, with the vendor callback looking like:

"
int tdx_pre_mmu_map_page(struct kvm_vcpu *vcpu,
struct kvm_map_memory *mapping,
u64 *error_code)
{
struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
struct kvm *kvm = vcpu->kvm;

if (!to_tdx(vcpu)->initialized)
return -EINVAL;

/* Shared-EPT case */
if (!(kvm_is_private_gpa(kvm, mapping->base_address)))
return 0;

/* Once TD is finalized, the initial guest memory is fixed. */
if (is_td_finalized(kvm_tdx))
return -EINVAL;

*error_code = TDX_SEPT_PFERR;
return 0;
}
"

kvm_is_private_gpa() check is already handled in this series.

The initialized and finalized checks are nice guard rails for userspace, but
shouldn't be strictly required.

The TDX_SEPT_PFERR is (PFERR_WRITE_MASK | PFERR_PRIVATE_ACCESS). The
PFERR_WRITE_MASK doesn't seem to be required. Isaku, what was the intention?

But, I think maybe we should add a hook back in the TDX series for the guard
rails.
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