hw/i386/acpi-build: Return a pre-computed _PRT table

When qemu runs without kvm acceleration the ACPI executions take a great
amount of time. If they take more than the default time (30sec), the
ACPI calls fail and the system might not behave correctly.

Now the _PRT table is computed on the fly. We can drastically reduce the
execution of the _PRT method if we return a pre-computed table.

Without this patch:
[   51.343484] ACPI Error: Aborting method \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
[   51.527032] ACPI Error: Method execution failed \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/uteval-68)
[   51.530049] virtio-pci 0000:00:02.0: can't derive routing for PCI INT A
[   51.530797] virtio-pci 0000:00:02.0: PCI INT A: no GSI
[   81.922901] ACPI Error: Aborting method \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
[   82.103534] ACPI Error: Method execution failed \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/uteval-68)
[   82.106088] virtio-pci 0000:00:04.0: can't derive routing for PCI INT A
[   82.106761] virtio-pci 0000:00:04.0: PCI INT A: no GSI
[  112.192568] ACPI Error: Aborting method \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
[  112.486687] ACPI Error: Method execution failed \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/uteval-68)
[  112.489554] virtio-pci 0000:00:05.0: can't derive routing for PCI INT A
[  112.490027] virtio-pci 0000:00:05.0: PCI INT A: no GSI
[  142.559448] ACPI Error: Aborting method \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
[  142.718596] ACPI Error: Method execution failed \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/uteval-68)
[  142.722889] virtio-pci 0000:00:06.0: can't derive routing for PCI INT A
[  142.724578] virtio-pci 0000:00:06.0: PCI INT A: no GSI

With this patch:
[   22.938076] ACPI: \_SB_.LNKB: Enabled at IRQ 10
[   24.214002] ACPI: \_SB_.LNKD: Enabled at IRQ 11
[   25.465170] ACPI: \_SB_.LNKA: Enabled at IRQ 10
[   27.944920] ACPI: \_SB_.LNKC: Enabled at IRQ 11

ACPI disassembly:
        Scope (PCI0)
        {
            Method (_PRT, 0, NotSerialized)  // _PRT: PCI Routing Table
            {
                Return (Package (0x80)
                {
                    Package (0x04)
                    {
                        0xFFFF,
                        Zero,
                        LNKD,
                        Zero
                    },

                    Package (0x04)
                    {
                        0xFFFF,
                        One,
                        LNKA,
                        Zero
                    },

                    Package (0x04)
                    {
                        0xFFFF,
                        0x02,
                        LNKB,
                        Zero
                    },

                    Package (0x04)
                    {
                        0xFFFF,
                        0x03,
                        LNKC,
                        Zero
                    },

                    Package (0x04)
                    {
                        0x0001FFFF,
                        Zero,
                        LNKS,
                        Zero
                    },
Context: https://lore.kernel.org/virtualization/20240417145544.38d7b482@imammedo.users.ipa.redhat.com/T/#t

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240814115736.1580337-3-ribalda@chromium.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

0 files changed, 0 insertions, 0 deletions