From 8332f0ed4f187c7b700831bd7cc83ce180a944b9 Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw@amazon.co.uk>
Date: Sat, 19 Nov 2022 09:25:39 +0000
Subject: [PATCH] KVM: Update gfn_to_pfn_cache khva when it moves within the
same page
In the case where a GPC is refreshed to a different location within the
same page, we didn't bother to update it. Mostly we don't need to, but
since the ->khva field also includes the offset within the page, that
does have to be updated.
Fixes: 3ba2c95ea180 ("KVM: Do not incorporate page offset into gfn=>pfn cache user address")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Cc: stable@kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
virt/kvm/pfncache.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index 346e47f155724..7c248193ca26e 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -297,7 +297,12 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
if (!gpc->valid || old_uhva != gpc->uhva) {
ret = hva_to_pfn_retry(kvm, gpc);
} else {
- /* If the HVA→PFN mapping was already valid, don't unmap it. */
+ /*
+ * If the HVA→PFN mapping was already valid, don't unmap it.
+ * But do update gpc->khva because the offset within the page
+ * may have changed.
+ */
+ gpc->khva = old_khva + page_offset;
old_pfn = KVM_PFN_ERR_FAULT;
old_khva = NULL;
ret = 0;
--
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