From dc9ce71e66b84497c375c529d818d8e8d0d793a9 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@intel.com>
Date: Thu, 9 Jan 2020 15:56:20 -0800
Subject: [PATCH] KVM: Return immediately if __kvm_gfn_to_hva_cache_init()
fails
Check the result of __kvm_gfn_to_hva_cache_init() and return immediately
instead of relying on the kvm_is_error_hva() check to detect errors so
that it's abundantly clear KVM intends to immediately bail on an error.
Note, the hva check is still mandatory to handle errors on subqeuesnt
calls with the same generation. Similarly, always return -EFAULT on
error so that multiple (bad) calls for a given generation will get the
same result, e.g. on an illegal gfn wrap, propagating the return from
__kvm_gfn_to_hva_cache_init() would cause the initial call to return
-EINVAL and subsequent calls to return -EFAULT.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
virt/kvm/kvm_main.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7fa56ccdbe500..ffec9f427b558 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2180,8 +2180,10 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
BUG_ON(len + offset > ghc->len);
- if (slots->generation != ghc->generation)
- __kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len);
+ if (slots->generation != ghc->generation) {
+ if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
+ return -EFAULT;
+ }
if (kvm_is_error_hva(ghc->hva))
return -EFAULT;
@@ -2213,8 +2215,10 @@ int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
BUG_ON(len > ghc->len);
- if (slots->generation != ghc->generation)
- __kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len);
+ if (slots->generation != ghc->generation) {
+ if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
+ return -EFAULT;
+ }
if (kvm_is_error_hva(ghc->hva))
return -EFAULT;
--
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