linux-kernel - [PATCH v2 06/15] KVM: Explicitly free allocated-but-unused dirty bitmap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20191022003537.13013-7-sean.j.christopherson@intel.com>
Date:   Mon, 21 Oct 2019 17:35:28 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     James Hogan <jhogan@...nel.org>,
        Paul Mackerras <paulus@...abs.org>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Marc Zyngier <maz@...nel.org>
Cc:     David Hildenbrand <david@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        linux-mips@...r.kernel.org, kvm-ppc@...r.kernel.org,
        kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu, linux-kernel@...r.kernel.org
Subject: [PATCH v2 06/15] KVM: Explicitly free allocated-but-unused dirty bitmap

Explicitly free an allocated-but-unused dirty bitmap instead of relying
on kvm_free_memslot() if an error occurs in __kvm_set_memory_region().
There is no longer a need to abuse kvm_free_memslot() to free arch
specific resources as arch specific code is now called only after the
common flow is guaranteed to succeed.  Arch code can still fail, but
it's responsible for its own cleanup in that case.

Eliminating the error path's abuse of kvm_free_memslot() paves the way
for simplifying kvm_free_memslot(), i.e. dropping its @dont param.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 virt/kvm/kvm_main.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6615c01b14a3..26151e2e3365 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1018,7 +1018,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
 
 	slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
 	if (!slots)
-		goto out_free;
+		goto out_bitmap;
 	memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
 
 	if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
@@ -1066,8 +1066,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
 		slots = install_new_memslots(kvm, as_id, slots);
 	kvfree(slots);
-out_free:
-	kvm_free_memslot(kvm, &new, &old);
+out_bitmap:
+	if (new.dirty_bitmap && !old.dirty_bitmap)
+		kvm_destroy_dirty_bitmap(&new);
 out:
 	return r;
 }
-- 
2.22.0