On Tue, 2023-11-21 at 18:02 +0000, Paul Durrant wrote:
>
> -static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa,
> +static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, u64 addr, bool addr_is_gpa,
> unsigned long len)
> {
> struct kvm_memslots *slots = kvm_memslots(gpc->kvm);
> - unsigned long page_offset = offset_in_page(gpa);
> + unsigned long page_offset = offset_in_page(addr);
> bool unmap_old = false;
> kvm_pfn_t old_pfn;
> bool hva_change = false;
> @@ -244,12 +244,21 @@ static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa,
> old_pfn = gpc->pfn;
> old_khva = (void *)PAGE_ALIGN_DOWN((uintptr_t)gpc->khva);
>
> - /* If the userspace HVA is invalid, refresh that first */
> - if (gpc->gpa != gpa || gpc->generation != slots->generation ||
> - kvm_is_error_hva(gpc->uhva)) {
> - gfn_t gfn = gpa_to_gfn(gpa);
> + if (!addr_is_gpa) {
> + gpc->gpa = KVM_XEN_INVALID_GPA;
> + gpc->uhva = PAGE_ALIGN_DOWN(gpc->uhva);
> + addr = PAGE_ALIGN_DOWN(addr);
> +
> + if (gpc->uhva != addr) {
> + gpc->uhva = addr;
> + hva_change = true;
> + }
> + } else if (gpc->gpa != addr ||
> + gpc->generation != slots->generation ||
> + kvm_is_error_hva(gpc->uhva)) {
> + gfn_t gfn = gpa_to_gfn(addr);
>
> - gpc->gpa = gpa;
> + gpc->gpa = addr;
> gpc->generation = slots->generation;
> gpc->memslot = __gfn_to_memslot(slots, gfn);
> gpc->uhva = gfn_to_hva_memslot(gpc->memslot, gfn);
Hrm, now that a previous patch means we're preserving the low bits of
gpc->uhva surely you don't *need* to mess with the gpc struct?
If gpc->gpa == KVM_XEN_INVALID_GPA (but gpc->uhva != KVM_ERR_ERR_BAD &&
gpc->active) surely that's enough to signal that gpc->uhva is canonical
and doesn't need to be looked up from the GPA?
And I think that means the 'bool addr_is_gpa' argument can go away from
__kvm_gpc_refresh(); you can set it up in {__,}kvm_gpc_activate*()
instead?
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