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Re: [RFC PATCH v3 3/7] hw/pci/pcie: Do not initialize slot capability if
From: |
Michael S. Tsirkin |
Subject: |
Re: [RFC PATCH v3 3/7] hw/pci/pcie: Do not initialize slot capability if acpihp is used |
Date: |
Thu, 24 Sep 2020 03:36:45 -0400 |
On Thu, Sep 24, 2020 at 09:00:09AM +0200, Julia Suvorova wrote:
> Instead of changing the hot-plug type in _OSC register, do not
> initialize the slot capability or set the 'Slot Implemented' flag.
> This way guest will choose ACPI hot-plug if it is preferred and leave
> the option to use SHPC with pcie-pci-bridge.
>
> Signed-off-by: Julia Suvorova <jusual@redhat.com>
> ---
> hw/i386/acpi-build.h | 2 ++
> hw/i386/acpi-build.c | 2 +-
> hw/pci/pcie.c | 16 ++++++++++++++++
> 3 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/hw/i386/acpi-build.h b/hw/i386/acpi-build.h
> index 487ec7710f..4c5bfb3d0b 100644
> --- a/hw/i386/acpi-build.h
> +++ b/hw/i386/acpi-build.h
> @@ -11,4 +11,6 @@ extern const struct AcpiGenericAddress
> x86_nvdimm_acpi_dsmio;
>
> void acpi_setup(void);
>
> +Object *object_resolve_type_unambiguous(const char *typename);
> +
> #endif
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index cf503b16af..b7811a8912 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -174,7 +174,7 @@ static void init_common_fadt_data(MachineState *ms,
> Object *o,
> *data = fadt;
> }
>
> -static Object *object_resolve_type_unambiguous(const char *typename)
> +Object *object_resolve_type_unambiguous(const char *typename)
> {
> bool ambig;
> Object *o = object_resolve_path_type("", typename, &ambig);
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index 5b48bae0f6..c1a082e8b9 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -27,6 +27,8 @@
> #include "hw/pci/pci_bus.h"
> #include "hw/pci/pcie_regs.h"
> #include "hw/pci/pcie_port.h"
> +#include "hw/i386/ich9.h"
> +#include "hw/i386/acpi-build.h"
> #include "qemu/range.h"
>
> //#define DEBUG_PCIE
Not really happy with pcie.c getting an i386 dependency.
> @@ -515,12 +517,26 @@ void pcie_cap_slot_unplug_request_cb(HotplugHandler
> *hotplug_dev,
> pcie_cap_slot_push_attention_button(hotplug_pdev);
> }
>
> +static bool acpi_pcihp_enabled(void)
> +{
> + Object *lpc = object_resolve_type_unambiguous(TYPE_ICH9_LPC_DEVICE);
> +
> + return lpc &&
> + object_property_get_bool(lpc,
> "acpi-pci-hotplug-with-bridge-support",
> + NULL);
> +
> +}
> +
Why not just check the property unconditionally?
> /* pci express slot for pci express root/downstream port
> PCI express capability slot registers */
> void pcie_cap_slot_init(PCIDevice *dev, PCIESlot *s)
> {
> uint32_t pos = dev->exp.exp_cap;
>
> + if (acpi_pcihp_enabled()) {
> + return;
> + }
> +
I think I would rather not teach pcie about acpi. How about we
change the polarity, name the property
"pci-native-hotplug" or whatever makes sense.
> pci_word_test_and_set_mask(dev->config + pos + PCI_EXP_FLAGS,
> PCI_EXP_FLAGS_SLOT);
>
> --
> 2.25.4