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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Lai Jiangshan <laijs@linux.alibaba.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Subject: [PATCH 4.19 50/50] kvm: check tlbs_dirty directly
Date: Mon, 22 Feb 2021 13:13:41 +0100
Message-ID: <20210222121027.317956650@linuxfoundation.org> (raw)
In-Reply-To: <20210222121019.925481519@linuxfoundation.org>

From: Lai Jiangshan <laijs@linux.alibaba.com>

commit 88bf56d04bc3564542049ec4ec168a8b60d0b48c upstream

In kvm_mmu_notifier_invalidate_range_start(), tlbs_dirty is used as:
        need_tlb_flush |= kvm->tlbs_dirty;
with need_tlb_flush's type being int and tlbs_dirty's type being long.

It means that tlbs_dirty is always used as int and the higher 32 bits
is useless.  We need to check tlbs_dirty in a correct way and this
change checks it directly without propagating it to need_tlb_flush.

Note: it's _extremely_ unlikely this neglecting of higher 32 bits can
cause problems in practice.  It would require encountering tlbs_dirty
on a 4 billion count boundary, and KVM would need to be using shadow
paging or be running a nested guest.

Cc: stable@vger.kernel.org
Fixes: a4ee1ca4a36e ("KVM: MMU: delay flush all tlbs on sync_page path")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20201217154118.16497-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 virt/kvm/kvm_main.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -412,9 +412,8 @@ static int kvm_mmu_notifier_invalidate_r
 	 */
 	kvm->mmu_notifier_count++;
 	need_tlb_flush = kvm_unmap_hva_range(kvm, start, end, blockable);
-	need_tlb_flush |= kvm->tlbs_dirty;
 	/* we've to flush the tlb before the pages can be freed */
-	if (need_tlb_flush)
+	if (need_tlb_flush || kvm->tlbs_dirty)
 		kvm_flush_remote_tlbs(kvm);
 
 	spin_unlock(&kvm->mmu_lock);



  parent reply index

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-22 12:12 [PATCH 4.19 00/50] 4.19.177-rc1 review Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 01/50] tracing: Do not count ftrace events in top level enable output Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 02/50] tracing: Check length before giving out the filter buffer Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 03/50] arm/xen: Dont probe xenbus as part of an early initcall Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 04/50] arm64: dts: rockchip: Fix PCIe DT properties on rk3399 Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 05/50] platform/x86: hp-wmi: Disable tablet-mode reporting by default Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 06/50] ovl: perform vfs_getxattr() with mounter creds Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 07/50] cap: fix conversions on getxattr Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 08/50] ovl: skip getxattr of security labels Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 09/50] drm/amd/display: Fix dc_sink kref count in emulated_link_detect Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 10/50] drm/amd/display: Free atomic state after drm_atomic_commit Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 11/50] riscv: virt_addr_valid must check the address belongs to linear mapping Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 12/50] bfq-iosched: Revert "bfq: Fix computation of shallow depth" Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 13/50] ARM: dts: lpc32xx: Revert set default clock rate of HCLK PLL Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 14/50] ARM: ensure the signal page contains defined contents Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 15/50] ARM: kexec: fix oops after TLB are invalidated Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 16/50] mt76: dma: fix a possible memory leak in mt76_add_fragment() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 17/50] bpf: Check for integer overflow when using roundup_pow_of_two() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 18/50] netfilter: xt_recent: Fix attempt to update deleted entry Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 19/50] netfilter: flowtable: fix tcp and udp header checksum update Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 20/50] xen/netback: avoid race in xenvif_rx_ring_slots_available() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 21/50] net: stmmac: set TxQ mode back to DCB after disabling CBS Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 22/50] netfilter: conntrack: skip identical origin tuple in same zone only Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 23/50] net: hns3: add a check for queue_id in hclge_reset_vf_queue() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 24/50] firmware_loader: align .builtin_fw to 8 Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 25/50] i2c: stm32f7: fix configuration of the digital filter Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 26/50] h8300: fix PREEMPTION build, TI_PRE_COUNT undefined Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 27/50] usb: dwc3: ulpi: fix checkpatch warning Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 28/50] usb: dwc3: ulpi: Replace CPU-based busyloop with Protocol-based one Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 29/50] net: fix iteration for sctp transport seq_files Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 30/50] net/vmw_vsock: improve locking in vsock_connect_timeout() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 31/50] net: watchdog: hold device global xmit lock during tx disable Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 32/50] vsock/virtio: update credit only if socket is not closed Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 33/50] vsock: fix locking in vsock_shutdown() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 34/50] net/rds: restrict iovecs length for RDS_CMSG_RDMA_ARGS Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 35/50] net/qrtr: restrict user-controlled length in qrtr_tun_write_iter() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 36/50] ovl: expand warning in ovl_d_real() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 37/50] x86/build: Disable CET instrumentation in the kernel for 32-bit too Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 38/50] KVM: SEV: fix double locking due to incorrect backport Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 39/50] net: qrtr: Fix port ID for control messages Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 40/50] Xen/x86: dont bail early from clear_foreign_p2m_mapping() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 41/50] Xen/x86: also check kernel mapping in set_foreign_p2m_mapping() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 42/50] Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 43/50] Xen/gntdev: correct error checking " Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 44/50] xen/arm: dont ignore return errors from set_phys_to_machine Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 45/50] xen-blkback: dont "handle" error by BUG() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 46/50] xen-netback: " Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 47/50] xen-scsiback: " Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 48/50] xen-blkback: fix error handling in xen_blkbk_map() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 49/50] scsi: qla2xxx: Fix crash during driver load on big endian machines Greg Kroah-Hartman
2021-02-22 12:13 ` Greg Kroah-Hartman [this message]
2021-02-22 18:40 ` [PATCH 4.19 00/50] 4.19.177-rc1 review Pavel Machek
2021-02-22 21:28 ` Guenter Roeck
2021-02-22 21:49 ` Igor
2021-02-23 10:10 ` Naresh Kamboju
2021-02-23 21:17 ` Shuah Khan

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