On Fri, 30 May 2014, Tiejun Chen wrote:
> Some registers of Intel IGD are mapped in host bridge, so it needs to
> passthrough these registers of physical host bridge to guest because
> emulated host bridge in guest doesn't have these mappings.
>
> The original patch is from Weidong Han < weidong.han @ intel.com >
>
> Signed-off-by: Yang Zhang <yang.z.zh...@intel.com>
> Signed-off-by: Tiejun Chen <tiejun.c...@intel.com>
> Cc: Weidong Han <weidong....@intel.com>
Reviewed-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
> v4:
>
> * Given that pci_create_pch() is called unconditionally, so we just return 0
> even if its failed to check xen_has_gfx_passthru.
> * Remove one spurious change.
>
> v3:
>
> * Improve comments to make that readable.
>
> v2:
>
> * To introduce is_igd_passthrough() to make sure we touch physical host bridge
> only in IGD case.
>
> hw/xen/xen_pt.h | 4 ++
> hw/xen/xen_pt_graphics.c | 162
> +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 166 insertions(+)
>
> diff --git a/hw/xen/xen_pt.h b/hw/xen/xen_pt.h
> index 4d3a18d..507165c 100644
> --- a/hw/xen/xen_pt.h
> +++ b/hw/xen/xen_pt.h
> @@ -302,5 +302,9 @@ extern int xen_has_gfx_passthru;
> int xen_pt_register_vga_regions(XenHostPCIDevice *dev);
> int xen_pt_unregister_vga_regions(XenHostPCIDevice *dev);
> int xen_pt_setup_vga(XenHostPCIDevice *dev);
> +int pci_create_pch(PCIBus *bus);
> +void igd_pci_write(PCIDevice *pci_dev, uint32_t config_addr,
> + uint32_t val, int len);
> +uint32_t igd_pci_read(PCIDevice *pci_dev, uint32_t config_addr, int len);
>
> #endif /* !XEN_PT_H */
> diff --git a/hw/xen/xen_pt_graphics.c b/hw/xen/xen_pt_graphics.c
> index 236b13a..c1f314a 100644
> --- a/hw/xen/xen_pt_graphics.c
> +++ b/hw/xen/xen_pt_graphics.c
> @@ -4,6 +4,7 @@
> #include "xen_pt.h"
> #include "xen-host-pci-device.h"
> #include "hw/xen/xen_backend.h"
> +#include "hw/pci/pci_bus.h"
>
> static int is_vga_passthrough(XenHostPCIDevice *dev)
> {
> @@ -289,3 +290,164 @@ static int create_pch_isa_bridge(PCIBus *bus,
> XenHostPCIDevice *hdev)
> XEN_PT_LOG(dev, "Intel PCH ISA bridge created.\n");
> return 0;
> }
> +
> +int pci_create_pch(PCIBus *bus)
> +{
> + XenHostPCIDevice hdev;
> + int r = 0;
> +
> + if (!xen_has_gfx_passthru) {
> + return r;
> + }
> +
> + r = xen_host_pci_device_get(&hdev, 0, 0, 0x1f, 0);
> + if (r) {
> + XEN_PT_ERR(NULL, "Failed to find Intel PCH on host\n");
> + goto err;
> + }
> +
> + if (hdev.vendor_id == PCI_VENDOR_ID_INTEL) {
> + r = create_pch_isa_bridge(bus, &hdev);
> + if (r) {
> + XEN_PT_ERR(NULL, "Failed to create PCH ISA bridge.\n");
> + goto err;
> + }
> + }
> +
> + xen_host_pci_device_put(&hdev);
> +
> +err:
> + return r;
> +}
> +
> +/*
> + * Currently we just pass this physical host bridge for IGD, 00:02.0.
> + *
> + * Here pci_dev is just that host bridge, so we have to get that real
> + * passthrough device by that given devfn to further confirm.
> + */
> +static int is_igd_passthrough(PCIDevice *pci_dev)
> +{
> + PCIDevice *f = pci_dev->bus->devices[PCI_DEVFN(2, 0)];
> + if (pci_dev->bus->devices[PCI_DEVFN(2, 0)]) {
> + XenPCIPassthroughState *s = DO_UPCAST(XenPCIPassthroughState, dev,
> f);
> + return (is_vga_passthrough(&s->real_device)
> + && (s->real_device.vendor_id == PCI_VENDOR_ID_INTEL));
> + } else {
> + return 0;
> + }
> +}
> +
> +void igd_pci_write(PCIDevice *pci_dev, uint32_t config_addr,
> + uint32_t val, int len)
> +{
> + XenHostPCIDevice dev;
> + int r;
> +
> + /* IGD read/write is through the host bridge.
> + * ISA bridge is only for detect purpose. In i915 driver it will
> + * probe ISA bridge to discover the IGD, see comment in i915_drv.c:
> + * intel_detect_pch():
> + * The reason to probe ISA bridge instead of Dev31:Fun0 is to
> + * make graphics device passthrough work easy for VMM, that only
> + * need to expose ISA bridge to let driver know the real hardware
> + * underneath. This is a requirement from virtualization team.
> + */
> +
> + assert(pci_dev->devfn == 0x00);
> +
> + if (!is_igd_passthrough(pci_dev)) {
> + goto write_default;
> + }
> +
> + switch (config_addr) {
> + case 0x58: /* PAVPC Offset */
> + break;
> + default:
> + /* Just sets the emulated values. */
> + goto write_default;
> + }
> +
> + /* Host write */
> + r = xen_host_pci_device_get(&dev, 0, 0, 0, 0);
> + if (r) {
> + XEN_PT_ERR(pci_dev, "Can't get pci_dev_host_bridge\n");
> + abort();
> + }
> +
> + r = xen_host_pci_set_block(&dev, config_addr, (uint8_t *)&val, len);
> + if (r) {
> + XEN_PT_ERR(pci_dev, "Can't get pci_dev_host_bridge\n");
> + abort();
> + }
> +
> + xen_host_pci_device_put(&dev);
> +
> + return;
> +
> +write_default:
> + pci_default_write_config(pci_dev, config_addr, val, len);
> +}
> +
> +uint32_t igd_pci_read(PCIDevice *pci_dev, uint32_t config_addr, int len)
> +{
> + XenHostPCIDevice dev;
> + uint32_t val;
> + int r;
> +
> + /* IGD read/write is through the host bridge.
> + * ISA bridge is only for detect purpose. In i915 driver it will
> + * probe ISA bridge to discover the IGD, see comment in i915_drv.c:
> + * intel_detect_pch():
> + * The reason to probe ISA bridge instead of Dev31:Fun0 is to
> + * make graphics device passthrough work easy for VMM, that only
> + * need to expose ISA bridge to let driver know the real hardware
> + * underneath. This is a requirement from virtualization team.
> + */
> + assert(pci_dev->devfn == 0x00);
> +
> + if (!is_igd_passthrough(pci_dev)) {
> + goto read_default;
> + }
> +
> + switch (config_addr) {
> + case 0x00: /* vendor id */
> + case 0x02: /* device id */
> + case 0x08: /* revision id */
> + case 0x2c: /* sybsystem vendor id */
> + case 0x2e: /* sybsystem id */
> + case 0x50: /* SNB: processor graphics control register */
> + case 0x52: /* processor graphics control register */
> + case 0xa0: /* top of memory */
> + case 0xb0: /* ILK: BSM: should read from dev 2 offset 0x5c */
> + case 0x58: /* SNB: PAVPC Offset */
> + case 0xa4: /* SNB: graphics base of stolen memory */
> + case 0xa8: /* SNB: base of GTT stolen memory */
> + break;
> + default:
> + /* Just gets the emulated values. */
> + goto read_default;
> + }
> +
> + /* Host read */
> + r = xen_host_pci_device_get(&dev, 0, 0, 0, 0);
> + if (r) {
> + goto err_out;
> + }
> +
> + r = xen_host_pci_get_block(&dev, config_addr, (uint8_t *)&val, len);
> + if (r) {
> + goto err_out;
> + }
> +
> + xen_host_pci_device_put(&dev);
> +
> + return val;
> +
> +read_default:
> + return pci_default_read_config(pci_dev, config_addr, len);
> +
> +err_out:
> + XEN_PT_ERR(pci_dev, "Can't get pci_dev_host_bridge\n");
> + return -1;
> +}
> --
> 1.9.1
>
