File hw-i386-acpi-build-Deny-control-on-PCIe-.patch of Package qemu

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File hw-i386-acpi-build-Deny-control-on-PCIe-.patch of Package qemu (Revision bf70aab340502a8abeb24ef35a85b752)

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From: Julia Suvorova <jusual@redhat.com>
Date: Fri, 12 Nov 2021 06:08:56 -0500
Subject: hw/i386/acpi-build: Deny control on PCIe Native Hot-plug in _OSC

Git-commit: 211afe5c69b597acf85fdd577eb497f5be1ffbd8
References: bsc#1192147

There are two ways to enable ACPI PCI Hot-plug:

* Disable the Hot-plug Capable bit on PCIe slots.

This was the first approach which led to regression [1-2], as
I/O space for a port is allocated only when it is hot-pluggable,
which is determined by HPC bit.

* Leave the HPC bit on and disable PCIe Native Hot-plug in _OSC
          method.

This removes the (future) ability of hot-plugging switches with PCIe
Native hotplug since ACPI PCI Hot-plug only works with cold-plugged
bridges. If the user wants to explicitely use this feature, they can
disable ACPI PCI Hot-plug with:
        --global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off

Change the bit in _OSC method so that the OS selects ACPI PCI Hot-plug
instead of PCIe Native.

[1] https://gitlab.com/qemu-project/qemu/-/issues/641
[2] https://bugzilla.redhat.com/show_bug.cgi?id=2006409

Signed-off-by: Julia Suvorova <jusual@redhat.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20211112110857.3116853-5-imammedo@redhat.com>
Reviewed-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Lin Ma <lma@suse.com>
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
---
 hw/i386/acpi-build.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index a33ac8b91e1baa129dac61ab32b6..ef28c3de772abe1cafe232f7754c 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1329,7 +1329,7 @@ static void build_x86_acpi_pci_hotplug(Aml *table, uint64_t pcihp_addr)
     aml_append(table, scope);
 }
 
-static Aml *build_q35_osc_method(void)
+static Aml *build_q35_osc_method(bool enable_native_pcie_hotplug)
 {
     Aml *if_ctx;
     Aml *if_ctx2;
@@ -1351,8 +1351,10 @@ static Aml *build_q35_osc_method(void)
     /*
      * Always allow native PME, AER (no dependencies)
      * Allow SHPC (PCI bridges can have SHPC controller)
+     * Disable PCIe Native Hot-plug if ACPI PCI Hot-plug is enabled.
      */
-    aml_append(if_ctx, aml_and(a_ctrl, aml_int(0x1F), a_ctrl));
+    aml_append(if_ctx, aml_and(a_ctrl,
+        aml_int(0x1E | (enable_native_pcie_hotplug ? 0x1 : 0x0)), a_ctrl));
 
     if_ctx2 = aml_if(aml_lnot(aml_equal(aml_arg(1), aml_int(1))));
     /* Unknown revision */
@@ -1441,7 +1443,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
         aml_append(dev, aml_name_decl("_UID", aml_int(pcmc->pci_root_uid)));
-        aml_append(dev, build_q35_osc_method());
+        aml_append(dev, build_q35_osc_method(!pm->pcihp_bridge_en));
         aml_append(sb_scope, dev);
         if (mcfg_valid) {
             aml_append(sb_scope, build_q35_dram_controller(&mcfg));
@@ -1557,7 +1559,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
             if (pci_bus_is_express(bus)) {
                 aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
                 aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
-                aml_append(dev, build_q35_osc_method());
+
+                /* Expander bridges do not have ACPI PCI Hot-plug enabled */
+                aml_append(dev, build_q35_osc_method(true));
             } else {
                 aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A03")));
             }

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File hw-i386-acpi-build-Deny-control-on-PCIe-.patch of Package qemu (Revision bf70aab340502a8abeb24ef35a85b752)

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