From 5488499f9c645d6c1ffe151be196df38ee5a56b4 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <seanjc@google.com>
Date: Thu, 10 Oct 2024 11:23:23 -0700
Subject: [PATCH] KVM: Explicitly initialize all fields at the start of
kvm_vcpu_map()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Explicitly initialize the entire kvm_host_map structure when mapping a
pfn, as some callers declare their struct on the stack, i.e. don't
zero-initialize the struct, which makes the map->hva in kvm_vcpu_unmap()
*very* suspect.
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-22-seanjc@google.com>
---
virt/kvm/kvm_main.c | 28 ++++++++++------------------
1 file changed, 10 insertions(+), 18 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 90e2a1f1de606..4074f49eb3f17 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3061,32 +3061,24 @@ void kvm_release_pfn(kvm_pfn_t pfn, bool dirty)
int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
{
- kvm_pfn_t pfn;
- void *hva = NULL;
- struct page *page = KVM_UNMAPPED_PAGE;
+ map->page = KVM_UNMAPPED_PAGE;
+ map->hva = NULL;
+ map->gfn = gfn;
- pfn = gfn_to_pfn(vcpu->kvm, gfn);
- if (is_error_noslot_pfn(pfn))
+ map->pfn = gfn_to_pfn(vcpu->kvm, gfn);
+ if (is_error_noslot_pfn(map->pfn))
return -EINVAL;
- if (pfn_valid(pfn)) {
- page = pfn_to_page(pfn);
- hva = kmap(page);
+ if (pfn_valid(map->pfn)) {
+ map->page = pfn_to_page(map->pfn);
+ map->hva = kmap(map->page);
#ifdef CONFIG_HAS_IOMEM
} else {
- hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
+ map->hva = memremap(pfn_to_hpa(map->pfn), PAGE_SIZE, MEMREMAP_WB);
#endif
}
- if (!hva)
- return -EFAULT;
-
- map->page = page;
- map->hva = hva;
- map->pfn = pfn;
- map->gfn = gfn;
-
- return 0;
+ return map->hva ? 0 : -EFAULT;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_map);
--
GitLab