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[PULL v4 38/48] Fix a gap where acpi_pcihp_find_hotplug_bus() returns a
From: |
Michael S. Tsirkin |
Subject: |
[PULL v4 38/48] Fix a gap where acpi_pcihp_find_hotplug_bus() returns a non-hotpluggable bus |
Date: |
Tue, 29 Sep 2020 03:22:33 -0400 |
From: Ani Sinha <ani@anisinha.ca>
When ACPI hotplug for the root bus is disabled, the bsel property for that
bus is not set. Please see the following commit:
3d7e78aa7777f ("Introduce a new flag for i440fx to disable PCI hotplug on the
root bus").
As a result, when acpi_pcihp_find_hotplug_bus() is called
with bsel set to 0, it may return the root bus. This can cause devices
attached to the root bus to get hot-unplugged if the user issues the following
set of commmands:
outl 0xae10 0
outl 0xae08 your_slot
Thanks to Julia for pointing this out here:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg734548.html
In this patch, we fix the issue in this function by checking if the bus which
is returned by the function is actually hotpluggable. If not, we simply return
NULL. This avoids the scenario where we were returning a non-hotpluggable bus.
Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200918084111.15339-5-ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/acpi/pcihp.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index 39b1f74442..32ae8b2c0a 100644
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -147,6 +147,21 @@ static PCIBus *acpi_pcihp_find_hotplug_bus(AcpiPciHpState
*s, int bsel)
if (!bsel && !find.bus) {
find.bus = s->root;
}
+
+ /*
+ * Check if find.bus is actually hotpluggable. If bsel is set to
+ * NULL for example on the root bus in order to make it
+ * non-hotpluggable, find.bus will match the root bus when bsel
+ * is 0. See acpi_pcihp_test_hotplug_bus() above. Since the
+ * bus is not hotpluggable however, we should not select the bus.
+ * Instead, we should set find.bus to NULL in that case. In the check
+ * below, we generalize this case for all buses, not just the root bus.
+ * The callers of this function check for a null return value and
+ * handle them appropriately.
+ */
+ if (find.bus && !qbus_is_hotpluggable(BUS(find.bus))) {
+ find.bus = NULL;
+ }
return find.bus;
}
--
MST
- [PULL v4 27/48] x86: acpi: introduce AcpiPmInfo::smi_on_cpuhp, (continued)
- [PULL v4 27/48] x86: acpi: introduce AcpiPmInfo::smi_on_cpuhp, Michael S. Tsirkin, 2020/09/29
- [PULL v4 28/48] x86: acpi: introduce the PCI0.SMI0 ACPI device, Michael S. Tsirkin, 2020/09/29
- [PULL v4 29/48] x68: acpi: trigger SMI before sending hotplug Notify event to OSPM, Michael S. Tsirkin, 2020/09/29
- [PULL v4 31/48] hw/smbios: support loading OEM strings values from a file, Michael S. Tsirkin, 2020/09/29
- [PULL v4 32/48] hw/smbios: report error if table size is too large, Michael S. Tsirkin, 2020/09/29
- [PULL v4 34/48] vhost-user: save features of multiqueues if chardev is closed, Michael S. Tsirkin, 2020/09/29
- [PULL v4 35/48] tests/acpi: mark addition of table DSDT.roothp for unit testing root pci hotplug, Michael S. Tsirkin, 2020/09/29
- [PULL v4 33/48] qemu-options: document SMBIOS type 11 settings, Michael S. Tsirkin, 2020/09/29
- [PULL v4 39/48] i440fx/acpi: do not add hotplug related amls for cold plugged bridges, Michael S. Tsirkin, 2020/09/29
- [PULL v4 36/48] tests/acpi: add new unit test to test hotplug off/on feature on the root pci bus, Michael S. Tsirkin, 2020/09/29
- [PULL v4 38/48] Fix a gap where acpi_pcihp_find_hotplug_bus() returns a non-hotpluggable bus,
Michael S. Tsirkin <=
- [PULL v4 40/48] tests/acpi: list added acpi table binary file for pci bridge hotplug test, Michael S. Tsirkin, 2020/09/29
- [PULL v4 37/48] tests/acpi: add a new ACPI table in order to test root pci hotplug on/off, Michael S. Tsirkin, 2020/09/29
- [PULL v4 41/48] tests/acpi: unit test for 'acpi-pci-hotplug-with-bridge-support' bridge flag, Michael S. Tsirkin, 2020/09/29
- [PULL v4 42/48] tests/acpi: add newly added acpi DSDT table blob for pci bridge hotplug flag, Michael S. Tsirkin, 2020/09/29
- [PULL v4 44/48] piix4: don't reserve hw resources when hotplug is off globally, Michael S. Tsirkin, 2020/09/29
- [PULL v4 43/48] Add ACPI DSDT tables for q35 that are being updated by the next patch, Michael S. Tsirkin, 2020/09/29
- [PULL v4 46/48] hw: virtio-pmem: detach the element fromt the virtqueue when error occurs, Michael S. Tsirkin, 2020/09/29
- [PULL v4 48/48] libvhost-user: return on error in vu_log_queue_fill(), Michael S. Tsirkin, 2020/09/29
- [PULL v4 12/48] virtio-pmem-pci: force virtio version 1, Michael S. Tsirkin, 2020/09/29
- [PULL v4 01/48] linux headers: sync to 5.9-rc4, Michael S. Tsirkin, 2020/09/29