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KVM: pfncache: Add a map helper function

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There is a pfncache unmap helper but mapping is open-coded. Arguably this
is fine because mapping is done in only one place, hva_to_pfn_retry(), but
adding the helper does make that function more readable.

No functional change intended.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20240215152916.1158-2-paul@xen.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Paul Durrant 2024-02-15 15:28:56 +00:00 committed by Sean Christopherson
parent db7d6fbc10
commit f39b80e3ff
1 changed files with 30 additions and 19 deletions
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49
virt/kvm/pfncache.c
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@ -96,17 +96,32 @@ bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, unsigned long len)
}
EXPORT_SYMBOL_GPL(kvm_gpc_check);
static void gpc_unmap_khva(kvm_pfn_t pfn, void *khva)
static void *gpc_map(kvm_pfn_t pfn)
{
if (pfn_valid(pfn))
return kmap(pfn_to_page(pfn));
#ifdef CONFIG_HAS_IOMEM
return memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
#else
return NULL;
#endif
}
static void gpc_unmap(kvm_pfn_t pfn, void *khva)
{
/* Unmap the old pfn/page if it was mapped before. */
if (!is_error_noslot_pfn(pfn) && khva) {
if (pfn_valid(pfn))
kunmap(pfn_to_page(pfn));
#ifdef CONFIG_HAS_IOMEM
else
memunmap(khva);
#endif
if (is_error_noslot_pfn(pfn) || !khva)
return;
if (pfn_valid(pfn)) {
kunmap(pfn_to_page(pfn));
return;
}
#ifdef CONFIG_HAS_IOMEM
memunmap(khva);
#endif
}
static inline bool mmu_notifier_retry_cache(struct kvm *kvm, unsigned long mmu_seq)
@ -175,7 +190,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc)
* the existing mapping and didn't create a new one.
*/
if (new_khva != old_khva)
gpc_unmap_khva(new_pfn, new_khva);
gpc_unmap(new_pfn, new_khva);
kvm_release_pfn_clean(new_pfn);
@ -193,15 +208,11 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc)
* too must be done outside of gpc->lock!
*/
if (gpc->usage & KVM_HOST_USES_PFN) {
if (new_pfn == gpc->pfn) {
if (new_pfn == gpc->pfn)
new_khva = old_khva;
} else if (pfn_valid(new_pfn)) {
new_khva = kmap(pfn_to_page(new_pfn));
#ifdef CONFIG_HAS_IOMEM
} else {
new_khva = memremap(pfn_to_hpa(new_pfn), PAGE_SIZE, MEMREMAP_WB);
#endif
}
else
new_khva = gpc_map(new_pfn);
if (!new_khva) {
kvm_release_pfn_clean(new_pfn);
goto out_error;
@ -326,7 +337,7 @@ out_unlock:
mutex_unlock(&gpc->refresh_lock);
if (unmap_old)
gpc_unmap_khva(old_pfn, old_khva);
gpc_unmap(old_pfn, old_khva);
return ret;
}
@ -412,7 +423,7 @@ void kvm_gpc_deactivate(struct gfn_to_pfn_cache *gpc)
list_del(&gpc->list);
spin_unlock(&kvm->gpc_lock);
gpc_unmap_khva(old_pfn, old_khva);
gpc_unmap(old_pfn, old_khva);
}
}
EXPORT_SYMBOL_GPL(kvm_gpc_deactivate);