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authorSean Christopherson <seanjc@google.com>2021-02-08 12:19:40 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2021-02-09 07:05:44 -0500
commita9545779ee9e9e103648f6f2552e73cfe808d0f4 (patch)
tree3f856b06ec070475aed277c354eb78519aae286f /virt
parent9fd6dad1261a541b3f5fa7dc5b152222306e6702 (diff)
KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped()
Use kvm_pfn_t, a.k.a. u64, for the local 'pfn' variable when retrieving a so called "remapped" hva/pfn pair. In theory, the hva could resolve to a pfn in high memory on a 32-bit kernel. This bug was inadvertantly exposed by commit bd2fae8da794 ("KVM: do not assume PTE is writable after follow_pfn"), which added an error PFN value to the mix, causing gcc to comlain about overflowing the unsigned long. arch/x86/kvm/../../../virt/kvm/kvm_main.c: In function ‘hva_to_pfn_remapped’: include/linux/kvm_host.h:89:30: error: conversion from ‘long long unsigned int’ to ‘long unsigned int’ changes value from ‘9218868437227405314’ to ‘2’ [-Werror=overflow] 89 | #define KVM_PFN_ERR_RO_FAULT (KVM_PFN_ERR_MASK + 2) | ^ virt/kvm/kvm_main.c:1935:9: note: in expansion of macro ‘KVM_PFN_ERR_RO_FAULT’ Cc: stable@vger.kernel.org Fixes: add6a0cd1c5b ("KVM: MMU: try to fix up page faults before giving up") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210208201940.1258328-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ee4ac2618ec5..001b9de4e727 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1906,7 +1906,7 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
bool write_fault, bool *writable,
kvm_pfn_t *p_pfn)
{
- unsigned long pfn;
+ kvm_pfn_t pfn;
pte_t *ptep;
spinlock_t *ptl;
int r;

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