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[PATCH 06/55] xen-bus: Fix backend state transition on device reset
From: |
Michael Roth |
Subject: |
[PATCH 06/55] xen-bus: Fix backend state transition on device reset |
Date: |
Tue, 5 Nov 2019 14:51:54 -0600 |
From: Anthony PERARD <address@hidden>
When a frontend wants to reset its state and the backend one, it
starts with setting "Closing", then waits for the backend (QEMU) to do
the same.
But when QEMU is setting "Closing" to its state, it triggers an event
(xenstore watch) that re-execute xen_device_backend_changed() and set
the backend state to "Closed". QEMU should wait for the frontend to
set "Closed" before doing the same.
Before setting "Closed" to the backend_state, we are also going to
check if there is a frontend. If that the case, when the backend state
is set to "Closing" the frontend should react and sets its state to
"Closing" then "Closed". The backend should wait for that to happen.
Fixes: b6af8926fb858c4f1426e5acb2cfc1f0580ec98a
Signed-off-by: Anthony PERARD <address@hidden>
Reviewed-by: Paul Durrant <address@hidden>
Message-Id: <address@hidden>
(cherry picked from commit cb3231460747552d70af9d546dc53d8195bcb796)
Signed-off-by: Michael Roth <address@hidden>
---
hw/xen/xen-bus.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index 7503eea9e9..5929aa4b2e 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -516,6 +516,23 @@ static void xen_device_backend_set_online(XenDevice
*xendev, bool online)
xen_device_backend_printf(xendev, "online", "%u", online);
}
+/*
+ * Tell from the state whether the frontend is likely alive,
+ * i.e. it will react to a change of state of the backend.
+ */
+static bool xen_device_state_is_active(enum xenbus_state state)
+{
+ switch (state) {
+ case XenbusStateInitWait:
+ case XenbusStateInitialised:
+ case XenbusStateConnected:
+ case XenbusStateClosing:
+ return true;
+ default:
+ return false;
+ }
+}
+
static void xen_device_backend_changed(void *opaque)
{
XenDevice *xendev = opaque;
@@ -539,11 +556,11 @@ static void xen_device_backend_changed(void *opaque)
/*
* If the toolstack (or unplug request callback) has set the backend
- * state to Closing, but there is no active frontend (i.e. the
- * state is not Connected) then set the backend state to Closed.
+ * state to Closing, but there is no active frontend then set the
+ * backend state to Closed.
*/
if (xendev->backend_state == XenbusStateClosing &&
- xendev->frontend_state != XenbusStateConnected) {
+ !xen_device_state_is_active(state)) {
xen_device_backend_set_state(xendev, XenbusStateClosed);
}
--
2.17.1
- [PATCH 42/55] hw/core/loader: Fix possible crash in rom_copy(), (continued)
- [PATCH 42/55] hw/core/loader: Fix possible crash in rom_copy(), Michael Roth, 2019/11/05
- [PATCH 45/55] mirror: Do not dereference invalid pointers, Michael Roth, 2019/11/05
- [PATCH 52/55] target/arm: Allow reading flags from FPSCR for M-profile, Michael Roth, 2019/11/05
- [PATCH 46/55] ui: Fix hanging up Cocoa display on macOS 10.15 (Catalina), Michael Roth, 2019/11/05
- [PATCH 50/55] util/hbitmap: strict hbitmap_reset, Michael Roth, 2019/11/05
- [PATCH 55/55] virtio-blk: Cancel the pending BH when the dataplane is reset, Michael Roth, 2019/11/05
- [PATCH 05/55] pc: Don't make die-id mandatory unless necessary, Michael Roth, 2019/11/05
- [PATCH 51/55] hbitmap: handle set/reset with zero length, Michael Roth, 2019/11/05
- [PATCH 08/55] block/file-posix: Reduce xfsctl() use, Michael Roth, 2019/11/05
- [PATCH 04/55] target/alpha: fix tlb_fill trap_arg2 value for instruction fetch, Michael Roth, 2019/11/05
- [PATCH 06/55] xen-bus: Fix backend state transition on device reset,
Michael Roth <=
- [PATCH 21/55] qcow2: Fix the calculation of the maximum L2 cache size, Michael Roth, 2019/11/05
- [PATCH 53/55] target/xtensa: regenerate and re-import test_mmuhifi_c3 core, Michael Roth, 2019/11/05
- [PATCH 25/55] curl: Check completion in curl_multi_do(), Michael Roth, 2019/11/05
- [PATCH 13/55] iotests: add testing shim for script-style python tests, Michael Roth, 2019/11/05
- [PATCH 41/55] vhost-user: save features if the char dev is closed, Michael Roth, 2019/11/05
- [PATCH 49/55] COLO-compare: Fix incorrect `if` logic, Michael Roth, 2019/11/05
- [PATCH 37/55] roms/Makefile.edk2: don't pull in submodules when building from tarball, Michael Roth, 2019/11/05
- [PATCH 54/55] scsi: lsi: exit infinite loop while executing script (CVE-2019-12068), Michael Roth, 2019/11/05
- [PATCH 40/55] iotests: Test internal snapshots with -blockdev, Michael Roth, 2019/11/05
- [PATCH 10/55] pr-manager: Fix invalid g_free() crash bug, Michael Roth, 2019/11/05