From 0e780da76a6fe283a20283856718bca3986c104f Mon Sep 17 00:00:00 2001 From: Ani Sinha Date: Thu, 16 Sep 2021 18:58:37 +0530 Subject: [PATCH] hw/i386/acpi: fix conflicting IO address range for acpi pci hotplug in q35 Change caf108bc58790 ("hw/i386/acpi-build: Add ACPI PCI hot-plug methods to Q35") selects an IO address range for acpi based PCI hotplug for q35 arbitrarily. It starts at address 0x0cc4 and ends at 0x0cdb. At the time when the patch was written but the final version of the patch was not yet pushed upstream, this address range was free and did not conflict with any other IO address ranges. However, with the following change, this address range was no longer conflict free as in this change, the IO address range (value of ACPI_PCIHP_SIZE) was incremented by four bytes: b32bd763a1ca92 ("pci: introduce acpi-index property for PCI device") This can be seen from the output of QMP command 'info mtree' : 0000000000000600-0000000000000603 (prio 0, i/o): acpi-evt 0000000000000604-0000000000000605 (prio 0, i/o): acpi-cnt 0000000000000608-000000000000060b (prio 0, i/o): acpi-tmr 0000000000000620-000000000000062f (prio 0, i/o): acpi-gpe0 0000000000000630-0000000000000637 (prio 0, i/o): acpi-smi 0000000000000cc4-0000000000000cdb (prio 0, i/o): acpi-pci-hotplug 0000000000000cd8-0000000000000ce3 (prio 0, i/o): acpi-cpu-hotplug It shows that there is a region of conflict between IO regions of acpi pci hotplug and acpi cpu hotplug. Unfortunately, the change caf108bc58790 did not update the IO address range appropriately before it was pushed upstream to accommodate the increased length of the IO address space introduced in change b32bd763a1ca92. Due to this bug, windows guests complain 'This device cannot find enough free resources it can use' in the device manager panel for extended IO buses. This issue also breaks the correct functioning of pci hotplug as the following shows that the IO space for pci hotplug has been truncated: (qemu) info mtree -f FlatView #0 AS "I/O", root: io Root memory region: io 0000000000000cc4-0000000000000cd7 (prio 0, i/o): acpi-pci-hotplug 0000000000000cd8-0000000000000cf7 (prio 0, i/o): acpi-cpu-hotplug Therefore, in this fix, we adjust the IO address range for the acpi pci hotplug so that it does not conflict with cpu hotplug and there is no truncation of IO spaces. The starting IO address of PCI hotplug region has been decremented by four bytes in order to accommodate four byte increment in the IO address space introduced by change b32bd763a1ca92 ("pci: introduce acpi-index property for PCI device") After fixing, the following are the corrected IO ranges: 0000000000000600-0000000000000603 (prio 0, i/o): acpi-evt 0000000000000604-0000000000000605 (prio 0, i/o): acpi-cnt 0000000000000608-000000000000060b (prio 0, i/o): acpi-tmr 0000000000000620-000000000000062f (prio 0, i/o): acpi-gpe0 0000000000000630-0000000000000637 (prio 0, i/o): acpi-smi 0000000000000cc0-0000000000000cd7 (prio 0, i/o): acpi-pci-hotplug 0000000000000cd8-0000000000000ce3 (prio 0, i/o): acpi-cpu-hotplug This change has been tested using a Windows Server 2019 guest VM. Windows no longer complains after this change. Fixes: caf108bc58790 ("hw/i386/acpi-build: Add ACPI PCI hot-plug methods to Q35") Resolves: https://gitlab.com/qemu-project/qemu/-/issues/561 Signed-off-by: Ani Sinha Reviewed-by: Igor Mammedov Reviewed-by: Julia Suvorova Message-Id: <20210916132838.3469580-3-ani@anisinha.ca> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- include/hw/acpi/ich9.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/hw/acpi/ich9.h b/include/hw/acpi/ich9.h index a329ce43ab..f04f1791bd 100644 --- a/include/hw/acpi/ich9.h +++ b/include/hw/acpi/ich9.h @@ -29,7 +29,7 @@ #include "hw/acpi/acpi_dev_interface.h" #include "hw/acpi/tco.h" -#define ACPI_PCIHP_ADDR_ICH9 0x0cc4 +#define ACPI_PCIHP_ADDR_ICH9 0x0cc0 typedef struct ICH9LPCPMRegs { /*