From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Jim Mattson <jmattson@google.com>,
Andrew Honig <ahonig@google.com>, Barret Rhoden <brho@google.com>
Subject: [PATCH 3/3] KVM: Return immediately if __kvm_gfn_to_hva_cache_init() fails
Date: Thu, 9 Jan 2020 15:56:20 -0800 [thread overview]
Message-ID: <20200109235620.6536-4-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200109235620.6536-1-sean.j.christopherson@intel.com>
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>
---
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 e8d8fc1d72b4..4479dc9ba00a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2205,8 +2205,10 @@ 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;
@@ -2238,8 +2240,10 @@ 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;
--
2.24.1
next prev parent reply other threads:[~2020-01-09 23:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-09 23:56 [PATCH 0/3] KVM: Clean up guest/host cache read/write code Sean Christopherson
2020-01-09 23:56 ` [PATCH 1/3] KVM: Check for a bad hva before dropping into the ghc slow path Sean Christopherson
2020-01-09 23:56 ` [PATCH 2/3] KVM: Clean up __kvm_gfn_to_hva_cache_init() and its callers Sean Christopherson
2020-01-09 23:56 ` Sean Christopherson [this message]
2020-01-21 13:51 ` [PATCH 0/3] KVM: Clean up guest/host cache read/write code Paolo Bonzini
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