linux-kernel - [PATCH 14/27] drm/i915/gvt: Don't bother removing write-protection on to-be-deleted slot

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]

Date:   Fri, 23 Dec 2022 00:57:26 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Zhenyu Wang <zhenyuw@...ux.intel.com>,
        Zhi Wang <zhi.a.wang@...el.com>
Cc:     kvm@...r.kernel.org, intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Yan Zhao <yan.y.zhao@...el.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: [PATCH 14/27] drm/i915/gvt: Don't bother removing write-protection on
 to-be-deleted slot

When handling a slot "flush", don't call back into KVM to drop write
protection for gfns in the slot.  Now that KVM rejects attempts to move
memory slots while KVMGT is attached, the only time a slot is "flushed"
is when it's being removed, i.e. the memslot and all its write-tracking
metadata is about to be deleted.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 5ff17a212107..3c59e7cd75d9 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1659,14 +1659,8 @@ static void kvmgt_page_track_flush_slot(struct kvm *kvm,
 	mutex_lock(&info->gfn_lock);
 	for (i = 0; i < slot->npages; i++) {
 		gfn = slot->base_gfn + i;
-		if (kvmgt_gfn_is_write_protected(info, gfn)) {
-			write_lock(&kvm->mmu_lock);
-			kvm_slot_page_track_remove_page(kvm, slot, gfn,
-						KVM_PAGE_TRACK_WRITE);
-			write_unlock(&kvm->mmu_lock);
-
+		if (kvmgt_gfn_is_write_protected(info, gfn))
 			kvmgt_protect_table_del(info, gfn);
-		}
 	}
 	mutex_unlock(&info->gfn_lock);
 }
-- 
2.39.0.314.g84b9a713c41-goog