Starting from Intel Core Ultra Series (Meteor Lake), Data Stolen Memory
has became a part of LMEMBAR (MMIO BAR2) [1][2], meaning that BDSM and
GGC register quirks are no longer needed on these platforms.
To support Meteor/Arrow/Lunar Lake and future IGD devices, remove the
generation limitation in IGD passthrough, and apply BDSM and GGC quirks
only to known Gen6-12 devices.
[1] https://edc.intel.com/content/www/us/en/design/publications/14th-generation-core-processors-cfg-and-mem-registers/d2-f0-processor-graphics-registers/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/i915/gem/i915_gem_stolen.c?h=v6.14#n142
Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
---
hw/vfio/igd.c | 58 +++++++++++++++++++--------------------------------
1 file changed, 21 insertions(+), 37 deletions(-)
diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index bc4c79837d..5b888616f0 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -103,6 +103,7 @@ static int igd_gen(VFIOPCIDevice *vdev)
/*
* Unfortunately, Intel changes it's specification quite often. This makes
* it impossible to use a suitable default value for unknown devices.
+ * Return -1 for not applying any generation-specific quirks.
*/
return -1;
}
@@ -434,20 +435,12 @@ void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int nr)
VFIOConfigMirrorQuirk *ggc_mirror, *bdsm_mirror;
int gen;
- /*
- * This must be an Intel VGA device at address 00:02.0 for us to even
- * consider enabling legacy mode. Some driver have dependencies on the PCI
- * bus address.
- */
if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
!vfio_is_vga(vdev) || nr != 0) {
return;
}
- /*
- * Only on IGD devices of gen 11 and above, the BDSM register is mirrored
- * into MMIO space and read from MMIO space by the Windows driver.
- */
+ /* Only on IGD Gen6-12 device needs quirks in BAR 0 */
gen = igd_gen(vdev);
if (gen < 6) {
return;
@@ -494,7 +487,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
{
g_autofree struct vfio_region_info *opregion = NULL;
int ret, gen;
- uint64_t gms_size;
+ uint64_t gms_size = 0;
uint64_t *bdsm_size;
uint32_t gmch;
bool legacy_mode_enabled = false;
@@ -514,18 +507,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
}
info_report("OpRegion detected on Intel display %x.", vdev->device_id);
- /*
- * IGD is not a standard, they like to change their specs often. We
- * only attempt to support back to SandBridge and we hope that newer
- * devices maintain compatibility with generation 8.
- */
gen = igd_gen(vdev);
- if (gen == -1) {
- error_report("IGD device %s is unsupported in legacy mode, "
- "try SandyBridge or newer", vdev->vbasedev.name);
- return true;
- }
-
gmch = vfio_pci_read_config(&vdev->pdev, IGD_GMCH, 4);
/*
@@ -624,32 +606,34 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
}
}
- gms_size = igd_stolen_memory_size(gen, gmch);
+ if (gen > 0) {
+ gms_size = igd_stolen_memory_size(gen, gmch);
+
+ /* BDSM is read-write, emulated. BIOS needs to be able to write it */
+ if (gen < 11) {
+ pci_set_long(vdev->pdev.config + IGD_BDSM, 0);
+ pci_set_long(vdev->pdev.wmask + IGD_BDSM, ~0);
+ pci_set_long(vdev->emulated_config_bits + IGD_BDSM, ~0);
+ } else {
+ pci_set_quad(vdev->pdev.config + IGD_BDSM_GEN11, 0);
+ pci_set_quad(vdev->pdev.wmask + IGD_BDSM_GEN11, ~0);
+ pci_set_quad(vdev->emulated_config_bits + IGD_BDSM_GEN11, ~0);
+ }
+ }
/*
* Request reserved memory for stolen memory via fw_cfg. VM firmware
* must allocate a 1MB aligned reserved memory region below 4GB with
- * the requested size (in bytes) for use by the Intel PCI class VGA
- * device at VM address 00:02.0. The base address of this reserved
- * memory region must be written to the device BDSM register at PCI
- * config offset 0x5C.
+ * the requested size (in bytes) for use by the IGD device. The base
+ * address of this reserved memory region must be written to the
+ * device BDSM register.
+ * For newer device without BDSM register, this fw_cfg item is 0.
*/
bdsm_size = g_malloc(sizeof(*bdsm_size));
*bdsm_size = cpu_to_le64(gms_size);
fw_cfg_add_file(fw_cfg_find(), "etc/igd-bdsm-size",
bdsm_size, sizeof(*bdsm_size));
- /* BDSM is read-write, emulated. The BIOS needs to be able to write it */
- if (gen < 11) {
- pci_set_long(vdev->pdev.config + IGD_BDSM, 0);
- pci_set_long(vdev->pdev.wmask + IGD_BDSM, ~0);
- pci_set_long(vdev->emulated_config_bits + IGD_BDSM, ~0);
- } else {
- pci_set_quad(vdev->pdev.config + IGD_BDSM_GEN11, 0);
- pci_set_quad(vdev->pdev.wmask + IGD_BDSM_GEN11, ~0);
- pci_set_quad(vdev->emulated_config_bits + IGD_BDSM_GEN11, ~0);
- }
-
trace_vfio_pci_igd_bdsm_enabled(vdev->vbasedev.name, (gms_size / MiB));
return true;
--
2.47.2On Tue, 2025-04-22 at 00:31 +0800, Tomita Moeko wrote:
> CAUTION: External Email!!
> Starting from Intel Core Ultra Series (Meteor Lake), Data Stolen Memory
> has became a part of LMEMBAR (MMIO BAR2) [1][2], meaning that BDSM and
> GGC register quirks are no longer needed on these platforms.
>
> To support Meteor/Arrow/Lunar Lake and future IGD devices, remove the
> generation limitation in IGD passthrough, and apply BDSM and GGC quirks
> only to known Gen6-12 devices.
>
> [1]
> https://nospamproxywebp.beckhoff.com/enQsig/link?id=BAgAAABHhgBhwX01GO0AAACNi-GgHiUI4sV0qRTHkaBvP5PrY5DqqTz9YhuTNO_iXQUZlCVu442aEFUtFJIN9H4QuJJwNJh5ry3XO19WptfEahlpGX9F7Nq8Xpv-GQ9_LZd6niU0I-kMcs9DxxlKk8E802ILvUeF86QyZP4D7A7AEaoUDo15UvzlwHlTOoUj4fzKJYvykniL_MlVr8H8FS2ySMcVqfE6IFb5Aiwhkq7hrpL53XHUYCVoK_y89PCzSWC-Y0fS5-Xo-SxRDOtI140aTd7KpmA39tf447LtBR1YQP8ccM8PjukqvroMpZtV3cDQcgya3EsmP0Fgrmc1
>
> [2]
> https://nospamproxywebp.beckhoff.com/enQsig/link?id=BAgAAABHhgBhwX01GNYAAAAtMYPOda9hw4SLBezXYKaYHKRl05pN8tzXcVl9njzCJlE1HkXUG-mljVszTJQKhcQYQTJNcuCekCys_GWgxsVTyOaS_NHFmHSUCZG_K4lK67xtRF6gmeuH6VTzSH0evGV976t_N2r5ADGfofxEA3bNt0iJmL1IzjhRilkRiNe-EmvdQ7DLMn1nAV9ZQCkPM5bCjIyd7MIjXMAlwhK4CraFMv1xw33w-ZnR0YrP4VIGHwKE7vUKp7-BjGZzyrgtwQ5m2SKD0zkEOs3dls5l351dSvNfqp740
>
>
> Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
> ---
> hw/vfio/igd.c | 58 +++++++++++++++++++--------------------------------
> 1 file changed, 21 insertions(+), 37 deletions(-)
>
> diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
> index bc4c79837d..5b888616f0 100644
> --- a/hw/vfio/igd.c
> +++ b/hw/vfio/igd.c
> @@ -103,6 +103,7 @@ static int igd_gen(VFIOPCIDevice *vdev)
> /*
> * Unfortunately, Intel changes it's specification quite often. This
> makes
> * it impossible to use a suitable default value for unknown devices.
> + * Return -1 for not applying any generation-specific quirks.
> */
> return -1;
> }
> @@ -434,20 +435,12 @@ void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int
> nr)
> VFIOConfigMirrorQuirk *ggc_mirror, *bdsm_mirror;
> int gen;
>
> - /*
> - * This must be an Intel VGA device at address 00:02.0 for us to even
> - * consider enabling legacy mode. Some driver have dependencies on the
> PCI
> - * bus address.
> - */
Same goes for this comment. It's not really correct as UEFI GOP and OS driver
depend on address 0:2.0 too but I'd keep and improve it to make it more clear
for future reader.
> if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
> !vfio_is_vga(vdev) || nr != 0) {
> return;
> }
>
> - /*
> - * Only on IGD devices of gen 11 and above, the BDSM register is mirrored
> - * into MMIO space and read from MMIO space by the Windows driver.
> - */
> + /* Only on IGD Gen6-12 device needs quirks in BAR 0 */
> gen = igd_gen(vdev);
> if (gen < 6) {
> return;
> @@ -494,7 +487,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev,
> Error **errp)
> {
> g_autofree struct vfio_region_info *opregion = NULL;
> int ret, gen;
> - uint64_t gms_size;
> + uint64_t gms_size = 0;
> uint64_t *bdsm_size;
> uint32_t gmch;
> bool legacy_mode_enabled = false;
> @@ -514,18 +507,7 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice
> *vdev, Error **errp)
> }
> info_report("OpRegion detected on Intel display %x.", vdev->device_id);
>
> - /*
> - * IGD is not a standard, they like to change their specs often. We
> - * only attempt to support back to SandBridge and we hope that newer
> - * devices maintain compatibility with generation 8.
> - */
> gen = igd_gen(vdev);
> - if (gen == -1) {
> - error_report("IGD device %s is unsupported in legacy mode, "
> - "try SandyBridge or newer", vdev-
> >https://nospamproxywebp.beckhoff.com/enQsig/link?id=BAgAAABHhgBhwX01GGwAAADNE
> nn7fAHvEAN3EJV6Ng4dOzKc7MR7f3e317FXOTfRW-ZxuzGFRyquEjUjSeP-
> 6ByDI2TtwvI3jwlJBjQdXL-V9t40AFbX3wSV_K-
> M0j4dDCcdYxjOhLKhEroDvVJ0XE20BM2QEteRk67iEFo1 );
> - return true;
> - }
> -
> gmch = vfio_pci_read_config(&vdev->pdev, IGD_GMCH, 4);
>
> /*
> @@ -624,32 +606,34 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice
> *vdev, Error **errp)
> }
> }
>
> - gms_size = igd_stolen_memory_size(gen, gmch);
> + if (gen > 0) {
> + gms_size = igd_stolen_memory_size(gen, gmch);
> +
> + /* BDSM is read-write, emulated. BIOS needs to be able to write it */
> + if (gen < 11) {
> + pci_set_long(vdev->pdev.config + IGD_BDSM, 0);
> + pci_set_long(vdev->pdev.wmask + IGD_BDSM, ~0);
> + pci_set_long(vdev->emulated_config_bits + IGD_BDSM, ~0);
> + } else {
> + pci_set_quad(vdev->pdev.config + IGD_BDSM_GEN11, 0);
> + pci_set_quad(vdev->pdev.wmask + IGD_BDSM_GEN11, ~0);
> + pci_set_quad(vdev->emulated_config_bits + IGD_BDSM_GEN11, ~0);
> + }
> + }
>
> /*
> * Request reserved memory for stolen memory via fw_cfg. VM firmware
> * must allocate a 1MB aligned reserved memory region below 4GB with
> - * the requested size (in bytes) for use by the Intel PCI class VGA
> - * device at VM address 00:02.0. The base address of this reserved
> - * memory region must be written to the device BDSM register at PCI
> - * config offset 0x5C.
> + * the requested size (in bytes) for use by the IGD device. The base
> + * address of this reserved memory region must be written to the
> + * device BDSM register.
> + * For newer device without BDSM register, this fw_cfg item is 0.
> */
> bdsm_size = g_malloc(sizeof(*bdsm_size));
> *bdsm_size = cpu_to_le64(gms_size);
> fw_cfg_add_file(fw_cfg_find(), "etc/igd-bdsm-size",
> bdsm_size, sizeof(*bdsm_size));
>
> - /* BDSM is read-write, emulated. The BIOS needs to be able to write it
> */
> - if (gen < 11) {
> - pci_set_long(vdev->pdev.config + IGD_BDSM, 0);
> - pci_set_long(vdev->pdev.wmask + IGD_BDSM, ~0);
> - pci_set_long(vdev->emulated_config_bits + IGD_BDSM, ~0);
> - } else {
> - pci_set_quad(vdev->pdev.config + IGD_BDSM_GEN11, 0);
> - pci_set_quad(vdev->pdev.wmask + IGD_BDSM_GEN11, ~0);
> - pci_set_quad(vdev->emulated_config_bits + IGD_BDSM_GEN11, ~0);
> - }
> -
> trace_vfio_pci_igd_bdsm_enabled(vdev-
> >https://nospamproxywebp.beckhoff.com/enQsig/link?id=BAgAAABHhgBhwX01GGwAAADNE
> nn7fAHvEAN3EJV6Ng4dOzKc7MR7f3e317FXOTfRW-ZxuzGFRyquEjUjSeP-
> 6ByDI2TtwvI3jwlJBjQdXL-V9t40AFbX3wSV_K-
> M0j4dDCcdYxjOhLKhEroDvVJ0XE20BM2QEteRk67iEFo1 , (gms_size / MiB));
>
> return true;
--
Kind regards,
Corvin
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