RE: [Xen-devel] [PATCH-for-5.0 v3 5/6] hw/pci-host/i440fx: Extract the IGD passthrough host bridge device

From: "Durrant, Paul" <pdurrant@amazon.com>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: Thomas Huth <thuth@redhat.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Paul Durrant <paul@xen.org>,
	Markus Armbruster <armbru@redhat.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Marcel Apfelbaum <marcel.apfelbaum@gmail.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Anthony Perard <anthony.perard@citrix.com>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: RE: [Xen-devel] [PATCH-for-5.0 v3 5/6] hw/pci-host/i440fx: Extract the IGD passthrough host bridge device
Date: Mon, 9 Dec 2019 10:08:04 +0000	[thread overview]
Message-ID: <1a3aea880e2640e88038e77f5bf14a13@EX13D32EUC003.ant.amazon.com> (raw)
In-Reply-To: <20191209095002.32194-6-philmd@redhat.com>

> -----Original Message-----
> From: Xen-devel <xen-devel-bounces@lists.xenproject.org> On Behalf Of
> Philippe Mathieu-Daudé
> Sent: 09 December 2019 09:50
> To: qemu-devel@nongnu.org
> Cc: Thomas Huth <thuth@redhat.com>; Stefano Stabellini
> <sstabellini@kernel.org>; Michael S. Tsirkin <mst@redhat.com>; Paul
> Durrant <paul@xen.org>; Markus Armbruster <armbru@redhat.com>; Alex
> Williamson <alex.williamson@redhat.com>; Marcel Apfelbaum
> <marcel.apfelbaum@gmail.com>; Paolo Bonzini <pbonzini@redhat.com>; Anthony
> Perard <anthony.perard@citrix.com>; xen-devel@lists.xenproject.org;
> Philippe Mathieu-Daudé <philmd@redhat.com>
> Subject: [Xen-devel] [PATCH-for-5.0 v3 5/6] hw/pci-host/i440fx: Extract
> the IGD passthrough host bridge device
> 
> We can use a i440FX without the IGD passthrough host bridge.
> Extract it into a new file, 'hw/pci-host/igd_pt.c'.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Acked-by: Paul Durrant <paul@xen.org>

> ---
> v3:
> - Rename as 'xen_igd_pt.c' (Alex Williamson)
> - Add an entry in MAINTAINERS::Xen
> ---
>  hw/pci-host/i440fx.c      |  84 --------------------------
>  hw/pci-host/xen_igd_pt.c  | 120 ++++++++++++++++++++++++++++++++++++++
>  MAINTAINERS               |   1 +
>  hw/pci-host/Makefile.objs |   1 +
>  4 files changed, 122 insertions(+), 84 deletions(-)
>  create mode 100644 hw/pci-host/xen_igd_pt.c
> 
> diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
> index 414138595b..bae7b42327 100644
> --- a/hw/pci-host/i440fx.c
> +++ b/hw/pci-host/i440fx.c
> @@ -368,89 +368,6 @@ static const TypeInfo i440fx_info = {
>      },
>  };
> 
> -/* IGD Passthrough Host Bridge. */
> -typedef struct {
> -    uint8_t offset;
> -    uint8_t len;
> -} IGDHostInfo;
> -
> -/* Here we just expose minimal host bridge offset subset. */
> -static const IGDHostInfo igd_host_bridge_infos[] = {
> -    {PCI_REVISION_ID,         2},
> -    {PCI_SUBSYSTEM_VENDOR_ID, 2},
> -    {PCI_SUBSYSTEM_ID,        2},
> -    {0x50,                    2}, /* SNB: processor graphics control
> register */
> -    {0x52,                    2}, /* processor graphics control register
> */
> -    {0xa4,                    4}, /* SNB: graphics base of stolen memory
> */
> -    {0xa8,                    4}, /* SNB: base of GTT stolen memory */
> -};
> -
> -static void host_pci_config_read(int pos, int len, uint32_t *val, Error
> **errp)
> -{
> -    int rc, config_fd;
> -    /* Access real host bridge. */
> -    char *path =
> g_strdup_printf("/sys/bus/pci/devices/%04x:%02x:%02x.%d/%s",
> -                                 0, 0, 0, 0, "config");
> -
> -    config_fd = open(path, O_RDWR);
> -    if (config_fd < 0) {
> -        error_setg_errno(errp, errno, "Failed to open: %s", path);
> -        goto out;
> -    }
> -
> -    if (lseek(config_fd, pos, SEEK_SET) != pos) {
> -        error_setg_errno(errp, errno, "Failed to seek: %s", path);
> -        goto out_close_fd;
> -    }
> -
> -    do {
> -        rc = read(config_fd, (uint8_t *)val, len);
> -    } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
> -    if (rc != len) {
> -        error_setg_errno(errp, errno, "Failed to read: %s", path);
> -    }
> -
> -out_close_fd:
> -    close(config_fd);
> -out:
> -    g_free(path);
> -}
> -
> -static void igd_pt_i440fx_realize(PCIDevice *pci_dev, Error **errp)
> -{
> -    uint32_t val = 0;
> -    size_t i;
> -    int pos, len;
> -    Error *local_err = NULL;
> -
> -    for (i = 0; i < ARRAY_SIZE(igd_host_bridge_infos); i++) {
> -        pos = igd_host_bridge_infos[i].offset;
> -        len = igd_host_bridge_infos[i].len;
> -        host_pci_config_read(pos, len, &val, &local_err);
> -        if (local_err) {
> -            error_propagate(errp, local_err);
> -            return;
> -        }
> -        pci_default_write_config(pci_dev, pos, val, len);
> -    }
> -}
> -
> -static void igd_passthrough_i440fx_class_init(ObjectClass *klass, void
> *data)
> -{
> -    DeviceClass *dc = DEVICE_CLASS(klass);
> -    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
> -
> -    k->realize = igd_pt_i440fx_realize;
> -    dc->desc = "IGD Passthrough Host bridge";
> -}
> -
> -static const TypeInfo igd_passthrough_i440fx_info = {
> -    .name          = TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE,
> -    .parent        = TYPE_I440FX_PCI_DEVICE,
> -    .instance_size = sizeof(PCII440FXState),
> -    .class_init    = igd_passthrough_i440fx_class_init,
> -};
> -
>  static const char *i440fx_pcihost_root_bus_path(PCIHostState
> *host_bridge,
>                                                  PCIBus *rootbus)
>  {
> @@ -495,7 +412,6 @@ static const TypeInfo i440fx_pcihost_info = {
>  static void i440fx_register_types(void)
>  {
>      type_register_static(&i440fx_info);
> -    type_register_static(&igd_passthrough_i440fx_info);
>      type_register_static(&i440fx_pcihost_info);
>  }
> 
> diff --git a/hw/pci-host/xen_igd_pt.c b/hw/pci-host/xen_igd_pt.c
> new file mode 100644
> index 0000000000..efcc9347ff
> --- /dev/null
> +++ b/hw/pci-host/xen_igd_pt.c
> @@ -0,0 +1,120 @@
> +/*
> + * QEMU Intel IGD Passthrough Host Bridge Emulation
> + *
> + * Copyright (c) 2006 Fabrice Bellard
> + *
> + * SPDX-License-Identifier: MIT
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining
> a copy
> + * of this software and associated documentation files (the "Software"),
> to deal
> + * in the Software without restriction, including without limitation the
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or
> sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be
> included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
> SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> IN
> + * THE SOFTWARE.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/pci/pci.h"
> +#include "hw/pci/pci_host.h"
> +#include "hw/pci-host/i440fx.h"
> +#include "qapi/error.h"
> +
> +typedef struct {
> +    uint8_t offset;
> +    uint8_t len;
> +} IGDHostInfo;
> +
> +/* Here we just expose minimal host bridge offset subset. */
> +static const IGDHostInfo igd_host_bridge_infos[] = {
> +    {PCI_REVISION_ID,         2},
> +    {PCI_SUBSYSTEM_VENDOR_ID, 2},
> +    {PCI_SUBSYSTEM_ID,        2},
> +    {0x50,                    2}, /* SNB: processor graphics control
> register */
> +    {0x52,                    2}, /* processor graphics control register
> */
> +    {0xa4,                    4}, /* SNB: graphics base of stolen memory
> */
> +    {0xa8,                    4}, /* SNB: base of GTT stolen memory */
> +};
> +
> +static void host_pci_config_read(int pos, int len, uint32_t *val, Error
> **errp)
> +{
> +    int rc, config_fd;
> +    /* Access real host bridge. */
> +    char *path =
> g_strdup_printf("/sys/bus/pci/devices/%04x:%02x:%02x.%d/%s",
> +                                 0, 0, 0, 0, "config");
> +
> +    config_fd = open(path, O_RDWR);
> +    if (config_fd < 0) {
> +        error_setg_errno(errp, errno, "Failed to open: %s", path);
> +        goto out;
> +    }
> +
> +    if (lseek(config_fd, pos, SEEK_SET) != pos) {
> +        error_setg_errno(errp, errno, "Failed to seek: %s", path);
> +        goto out_close_fd;
> +    }
> +
> +    do {
> +        rc = read(config_fd, (uint8_t *)val, len);
> +    } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
> +    if (rc != len) {
> +        error_setg_errno(errp, errno, "Failed to read: %s", path);
> +    }
> +
> + out_close_fd:
> +    close(config_fd);
> + out:
> +    g_free(path);
> +}
> +
> +static void igd_pt_i440fx_realize(PCIDevice *pci_dev, Error **errp)
> +{
> +    uint32_t val = 0;
> +    size_t i;
> +    int pos, len;
> +    Error *local_err = NULL;
> +
> +    for (i = 0; i < ARRAY_SIZE(igd_host_bridge_infos); i++) {
> +        pos = igd_host_bridge_infos[i].offset;
> +        len = igd_host_bridge_infos[i].len;
> +        host_pci_config_read(pos, len, &val, &local_err);
> +        if (local_err) {
> +            error_propagate(errp, local_err);
> +            return;
> +        }
> +        pci_default_write_config(pci_dev, pos, val, len);
> +    }
> +}
> +
> +static void igd_passthrough_i440fx_class_init(ObjectClass *klass, void
> *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
> +
> +    k->realize = igd_pt_i440fx_realize;
> +    dc->desc = "IGD Passthrough Host bridge";
> +}
> +
> +static const TypeInfo igd_passthrough_i440fx_info = {
> +    .name          = TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE,
> +    .parent        = TYPE_I440FX_PCI_DEVICE,
> +    .instance_size = sizeof(PCII440FXState),
> +    .class_init    = igd_passthrough_i440fx_class_init,
> +};
> +
> +static void igd_pt_i440fx_register_types(void)
> +{
> +    type_register_static(&igd_passthrough_i440fx_info);
> +}
> +
> +type_init(igd_pt_i440fx_register_types)
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5e5e3e52d6..62bcf5e94e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -419,6 +419,7 @@ F: hw/block/dataplane/xen*
>  F: hw/xen/
>  F: hw/xenpv/
>  F: hw/i386/xen/
> +F: hw/pci-host/xen_igd_pt.c
>  F: include/hw/block/dataplane/xen*
>  F: include/hw/xen/
>  F: include/sysemu/xen-mapcache.h
> diff --git a/hw/pci-host/Makefile.objs b/hw/pci-host/Makefile.objs
> index efd752b766..fa6d1556c0 100644
> --- a/hw/pci-host/Makefile.objs
> +++ b/hw/pci-host/Makefile.objs
> @@ -14,6 +14,7 @@ common-obj-$(CONFIG_VERSATILE_PCI) += versatile.o
>  common-obj-$(CONFIG_PCI_SABRE) += sabre.o
>  common-obj-$(CONFIG_FULONG) += bonito.o
>  common-obj-$(CONFIG_PCI_I440FX) += i440fx.o
> +common-obj-$(CONFIG_PCI_I440FX) += xen_igd_pt.o
>  common-obj-$(CONFIG_PCI_EXPRESS_Q35) += q35.o
>  common-obj-$(CONFIG_PCI_EXPRESS_GENERIC_BRIDGE) += gpex.o
>  common-obj-$(CONFIG_PCI_EXPRESS_XILINX) += xilinx-pcie.o
> --
> 2.21.0
> 
> 
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