[PATCH v3 04/13] KVM: pfncache: base offset check on khva rather than gpa

From: Paul Durrant
Date: Mon Sep 18 2023 - 12:34:12 EST


From: Paul Durrant <pdurrant@xxxxxxxxxx>

After a subsequent patch, the gpa may not always be set whereas khva will
(as long as the cache valid flag is also set).

No functional change intended.

Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
Reviewed-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
virt/kvm/pfncache.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index 17afbb464a70..37bcb4399780 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -83,15 +83,18 @@ bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, unsigned long len)
if (!gpc->active)
return false;

- if ((gpc->gpa & ~PAGE_MASK) + len > PAGE_SIZE)
+ if (gpc->generation != slots->generation)
return false;

- if (gpc->generation != slots->generation || kvm_is_error_hva(gpc->uhva))
+ if (kvm_is_error_hva(gpc->uhva))
return false;

if (!gpc->valid)
return false;

+ if (offset_in_page(gpc->khva) + len > PAGE_SIZE)
+ return false;
+
return true;
}
EXPORT_SYMBOL_GPL(kvm_gpc_check);
--
2.39.2