| From | Kamal Mostafa <> | Subject | [PATCH 3.13.y-ckt 83/95] KVM: use slowpath for cross page cached accesses | Date | Wed, 27 May 2015 12:00:31 -0700 |
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3.13.11-ckt21 -stable review patch. If anyone has any objections, please let me know.
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From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>
commit ca3f0874723fad81d0c701b63ae3a17a408d5f25 upstream.
kvm_write_guest_cached() does not mark all written pages as dirty and code comments in kvm_gfn_to_hva_cache_init() talk about NULL memslot with cross page accesses. Fix all the easy way.
The check is '<= 1' to have the same result for 'len = 0' cache anywhere in the page. (nr_pages_needed is 0 on page boundary.)
Fixes: 8f964525a121 ("KVM: Allow cross page reads and writes from cached translations.") Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Message-Id: <20150408121648.GA3519@potion.brq.redhat.com> Reviewed-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- virt/kvm/kvm_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8d2a98a..db50f4c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1559,8 +1559,8 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, ghc->generation = slots->generation; ghc->len = len; ghc->memslot = gfn_to_memslot(kvm, start_gfn); - ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn, &nr_pages_avail); - if (!kvm_is_error_hva(ghc->hva) && nr_pages_avail >= nr_pages_needed) { + ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn, NULL); + if (!kvm_is_error_hva(ghc->hva) && nr_pages_needed <= 1) { ghc->hva += offset; } else { /* -- 1.9.1
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