On Tue, 14 Sep 2021 10:24:09 +0530 Ani Sinha <a...@anisinha.ca> wrote:
> 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 accomodate 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 accomodate 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 <a...@anisinha.ca> Reviewed-by: Igor Mammedov <imamm...@redhat.com> > --- > 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 { > /*