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Re: [Qemu-devel] [PATCH for-2.10 v2 1/2] hw/acpi: Call acpi_set_pci_info
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH for-2.10 v2 1/2] hw/acpi: Call acpi_set_pci_info when no ACPI tables needed |
Date: |
Tue, 15 Aug 2017 14:07:51 +0200 |
On Tue, 15 Aug 2017 12:15:48 +0100
Anthony PERARD <address@hidden> wrote:
> To do PCI passthrough with Xen, the property acpi-pcihp-bsel needs to be
> set, but this was done only when ACPI tables are built which is not
> needed for a Xen guest. The need for the property starts with commit
> "pc: pcihp: avoid adding ACPI_PCIHP_PROP_BSEL twice"
> (f0c9d64a68b776374ec4732424a3e27753ce37b6).
>
> Set pci info before checking for the needs to build ACPI tables.
>
> Assign bsel=0 property only to the root bus on Xen as there is no
> support in the Xen ACPI tables for a different value.
looking at hw/acpi/pcihp.c and bsel usage there it looks like
bsel property is owned by it and not by ACPI tables, so instead of
shuffling it in acpi_setup(), how about moving bsel initialization
to hw/acpi/pcihp.c and initialize it there unconditionally?
It could be as simple as moving acpi_set_pci_info()/acpi_set_bsel()
there and calling it from acpi_pcihp_reset().
Then there won't be need for Xen specific branches, as root bus
will have bsel set automatically which is sufficient for Xen and
the rest of bsel-s (bridges) will be just unused by Xen,
which could later extend its ACPI table implementation to utilize them.
> Reported-by: Sander Eikelenboom <address@hidden>
> Signed-off-by: Anthony PERARD <address@hidden>
>
> ---
> Changes in V2:
> - check for acpi_enabled before calling acpi_set_pci_info.
> - set the property on the root bus only.
>
> This patch would be a canditade to backport to 2.9.
>
> CC: Stefano Stabellini <address@hidden>
> CC: Bruce Rogers <address@hidden>
> ---
> hw/i386/acpi-build.c | 25 ++++++++++++++++---------
> 1 file changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 98dd424678..c0483b96cf 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -46,6 +46,7 @@
> #include "sysemu/tpm_backend.h"
> #include "hw/timer/mc146818rtc_regs.h"
> #include "sysemu/numa.h"
> +#include "hw/xen/xen.h"
>
> /* Supported chipsets: */
> #include "hw/acpi/piix4.h"
> @@ -518,8 +519,13 @@ static void acpi_set_pci_info(void)
> unsigned bsel_alloc = ACPI_PCIHP_BSEL_DEFAULT;
>
> if (bus) {
> - /* Scan all PCI buses. Set property to enable acpi based hotplug. */
> - pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL, &bsel_alloc);
> + if (xen_enabled()) {
> + /* Assign BSEL property to root bus only. */
> + acpi_set_bsel(bus, &bsel_alloc);
> + } else {
> + /* Scan all PCI buses. Set property to enable acpi based
> hotplug. */
> + pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL,
> &bsel_alloc);
> + }
> }
> }
>
> @@ -2871,6 +2877,14 @@ void acpi_setup(void)
> AcpiBuildState *build_state;
> Object *vmgenid_dev;
>
> + if (!acpi_enabled) {
> + ACPI_BUILD_DPRINTF("ACPI disabled. Bailing out.\n");
> + return;
> + }
> +
> + /* Assign BSEL property on hotpluggable PCI buses. */
> + acpi_set_pci_info();
> +
> if (!pcms->fw_cfg) {
> ACPI_BUILD_DPRINTF("No fw cfg. Bailing out.\n");
> return;
> @@ -2881,15 +2895,8 @@ void acpi_setup(void)
> return;
> }
>
> - if (!acpi_enabled) {
> - ACPI_BUILD_DPRINTF("ACPI disabled. Bailing out.\n");
> - return;
> - }
> -
> build_state = g_malloc0(sizeof *build_state);
>
> - acpi_set_pci_info();
> -
> acpi_build_tables_init(&tables);
> acpi_build(&tables, MACHINE(pcms));
>
[Qemu-devel] [PATCH for-2.10 v2 2/2] Revert "ACPI: don't call acpi_pcihp_device_plug_cb on xen", Anthony PERARD, 2017/08/15