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Paul Durrantsean-jc
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KVM: pfncache: Add a map helper function
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>
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virt/kvm/pfncache.c

Lines changed: 29 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -96,17 +96,32 @@ bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, unsigned long len)
9696
}
9797
EXPORT_SYMBOL_GPL(kvm_gpc_check);
9898

99-
static void gpc_unmap_khva(kvm_pfn_t pfn, void *khva)
99+
static void *gpc_map(kvm_pfn_t pfn)
100100
{
101-
/* Unmap the old pfn/page if it was mapped before. */
102-
if (!is_error_noslot_pfn(pfn) && khva) {
103-
if (pfn_valid(pfn))
104-
kunmap(pfn_to_page(pfn));
101+
if (pfn_valid(pfn))
102+
return kmap(pfn_to_page(pfn));
103+
105104
#ifdef CONFIG_HAS_IOMEM
106-
else
107-
memunmap(khva);
105+
return memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
106+
#else
107+
return NULL;
108108
#endif
109+
}
110+
111+
static void gpc_unmap(kvm_pfn_t pfn, void *khva)
112+
{
113+
/* Unmap the old pfn/page if it was mapped before. */
114+
if (is_error_noslot_pfn(pfn) || !khva)
115+
return;
116+
117+
if (pfn_valid(pfn)) {
118+
kunmap(pfn_to_page(pfn));
119+
return;
109120
}
121+
122+
#ifdef CONFIG_HAS_IOMEM
123+
memunmap(khva);
124+
#endif
110125
}
111126

112127
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)
175190
* the existing mapping and didn't create a new one.
176191
*/
177192
if (new_khva != old_khva)
178-
gpc_unmap_khva(new_pfn, new_khva);
193+
gpc_unmap(new_pfn, new_khva);
179194

180195
kvm_release_pfn_clean(new_pfn);
181196

@@ -193,15 +208,11 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc)
193208
* too must be done outside of gpc->lock!
194209
*/
195210
if (gpc->usage & KVM_HOST_USES_PFN) {
196-
if (new_pfn == gpc->pfn) {
211+
if (new_pfn == gpc->pfn)
197212
new_khva = old_khva;
198-
} else if (pfn_valid(new_pfn)) {
199-
new_khva = kmap(pfn_to_page(new_pfn));
200-
#ifdef CONFIG_HAS_IOMEM
201-
} else {
202-
new_khva = memremap(pfn_to_hpa(new_pfn), PAGE_SIZE, MEMREMAP_WB);
203-
#endif
204-
}
213+
else
214+
new_khva = gpc_map(new_pfn);
215+
205216
if (!new_khva) {
206217
kvm_release_pfn_clean(new_pfn);
207218
goto out_error;
@@ -326,7 +337,7 @@ static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa,
326337
mutex_unlock(&gpc->refresh_lock);
327338

328339
if (unmap_old)
329-
gpc_unmap_khva(old_pfn, old_khva);
340+
gpc_unmap(old_pfn, old_khva);
330341

331342
return ret;
332343
}
@@ -412,7 +423,7 @@ void kvm_gpc_deactivate(struct gfn_to_pfn_cache *gpc)
412423
list_del(&gpc->list);
413424
spin_unlock(&kvm->gpc_lock);
414425

415-
gpc_unmap_khva(old_pfn, old_khva);
426+
gpc_unmap(old_pfn, old_khva);
416427
}
417428
}
418429
EXPORT_SYMBOL_GPL(kvm_gpc_deactivate);

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