[PATCH v13 21/85] KVM: Explicitly initialize all fields at the start of kvm_vcpu_map()
From: Sean Christopherson <seanjc@google.com>
Date: 2024-10-10 18:25:37
Also in:
kvm, kvm-riscv, kvmarm, linux-arm-kernel, linux-mips, linux-riscv, lkml, loongarch
Subsystem:
kernel virtual machine (kvm), the rest · Maintainers:
Paolo Bonzini, Linus Torvalds
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 <redacted> Signed-off-by: Sean Christopherson <seanjc@google.com> --- virt/kvm/kvm_main.c | 40 ++++++++++++++++------------------------ 1 file changed, 16 insertions(+), 24 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c7691bc40389..f1c9a781315c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c@@ -3067,32 +3067,24 @@ 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; - - pfn = gfn_to_pfn(vcpu->kvm, gfn); - if (is_error_noslot_pfn(pfn)) - return -EINVAL; - - if (pfn_valid(pfn)) { - page = pfn_to_page(pfn); - hva = kmap(page); -#ifdef CONFIG_HAS_IOMEM - } else { - hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB); -#endif - } - - if (!hva) - return -EFAULT; - - map->page = page; - map->hva = hva; - map->pfn = pfn; + map->page = KVM_UNMAPPED_PAGE; + map->hva = NULL; map->gfn = gfn; - return 0; + map->pfn = gfn_to_pfn(vcpu->kvm, gfn); + if (is_error_noslot_pfn(map->pfn)) + return -EINVAL; + + if (pfn_valid(map->pfn)) { + map->page = pfn_to_page(map->pfn); + map->hva = kmap(map->page); +#ifdef CONFIG_HAS_IOMEM + } else { + map->hva = memremap(pfn_to_hpa(map->pfn), PAGE_SIZE, MEMREMAP_WB); +#endif + } + + return map->hva ? 0 : -EFAULT; } EXPORT_SYMBOL_GPL(kvm_vcpu_map);
--
2.47.0.rc1.288.g06298d1525-goog