Re: [PATCH v2 09/12] Retry fault before vmentry

Avi Kivity
2009-11-25T13:09:36Z

On 11/23/2009 04:06 PM, Gleb Natapov wrote:
> When page is swapped in it is mapped into guest memory only after guest
> tries to access it again and generate another fault. To save this fault
> we can map it immediately since we know that guest is going to access
> the page.
>
>
> -static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
> +static int tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t cr3, gva_t gpa,
> u32 error_code)
> {
> pfn_t pfn;
> @@ -2230,7 +2233,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
> mmu_seq = vcpu->kvm->mmu_notifier_seq;
> smp_rmb();
>
> - if (can_do_async_pf(vcpu)) {
> + if (cr3 == vcpu->arch.cr3&& can_do_async_pf(vcpu)) {
>

Why check cr3 here?

> -static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
> +static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t cr3, gva_t addr,
> u32 error_code)
>

I'd be slightly happier if we had a page_fault_other_cr3() op that
switched cr3, called the original, then switched back (the tdp version
need not change anything).

--
error compiling committee.c: too many arguments to function