[qemu-xen staging-4.16] hw/i386/acpi: fix conflicting IO address range for acpi pci hotplug in q35

[patchbot@xxxxxxx]

commit 9e80a430ed5996734ef35c457d793b8106f16d15
Author:     Ani Sinha <ani@xxxxxxxxxxx>
AuthorDate: Thu Sep 16 18:58:37 2021 +0530
Commit:     Michael Roth <michael.roth@xxxxxxx>
CommitDate: Tue Dec 14 13:12:38 2021 -0600

    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 <ani@xxxxxxxxxxx>
    Reviewed-by: Igor Mammedov <imammedo@xxxxxxxxxx>
    Reviewed-by: Julia Suvorova <jusual@xxxxxxxxxx>
    Message-Id: <20210916132838.3469580-3-ani@xxxxxxxxxxx>
    Reviewed-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    (cherry picked from commit 0e780da76a6fe283a20283856718bca3986c104f)
    Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
---
 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 {
     /*
--
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