On Tue, 2025-04-22 at 00:31 +0800, Tomita Moeko wrote:
> CAUTION: External Email!!
> On Gen9 and later IGD devices, GMS 0xf0 to 0xfe represents 4MB to 60MB
> pre-allocated memory size in 4MB increments. Allow users overriding
> GMS with these values.
>
> Signed-off-by: Tomita Moeko <tomitamo...@gmail.com>
> ---
> hw/vfio/igd.c | 59 +++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 41 insertions(+), 18 deletions(-)
>
> diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
> index e3ff86d0e6..b747fdfaeb 100644
> --- a/hw/vfio/igd.c
> +++ b/hw/vfio/igd.c
> @@ -387,6 +387,44 @@ static bool vfio_pci_igd_setup_lpc_bridge(VFIOPCIDevice
> *vdev, Error **errp)
> return true;
> }
>
> +static bool vfio_pci_igd_override_gms(int gen, uint32_t gms, uint32_t *gmch)
> +{
> + bool ret = false;
> +
> + if (gen == -1) {
> + error_report("x-igd-gms is not supported on this device");
> + } else if (gen < 8) {
> + if (gms <= 0x10) {
> + *gmch &= ~(IGD_GMCH_GEN6_GMS_MASK << IGD_GMCH_GEN6_GMS_SHIFT);
> + *gmch |= gms << IGD_GMCH_GEN6_GMS_SHIFT;
> + ret = true;
> + } else {
> + error_report(QERR_INVALID_PARAMETER_VALUE, "x-igd-gms",
> "0~0x10");
> + }
> + } else if (gen == 8) {
> + if ((gms <= 0x40)) {
nit: you can remove a parantheses pair.
> + *gmch &= ~(IGD_GMCH_GEN8_GMS_MASK << IGD_GMCH_GEN8_GMS_SHIFT);
> + *gmch |= gms << IGD_GMCH_GEN8_GMS_SHIFT;
> + ret = true;
> + } else {
> + error_report(QERR_INVALID_PARAMETER_VALUE, "x-igd-gms",
> "0~0x40");
> + }
> + } else {
> + /* 0x0 to 0x40: 32MB increments starting at 0MB */
> + /* 0xf0 to 0xfe: 4MB increments starting at 4MB */
> + if ((gms <= 0x40) || (gms >= 0xf0 && gms <= 0xfe)) {
> + *gmch &= ~(IGD_GMCH_GEN8_GMS_MASK << IGD_GMCH_GEN8_GMS_SHIFT);
> + *gmch |= gms << IGD_GMCH_GEN8_GMS_SHIFT;
> + ret = true;
> + } else {
> + error_report(QERR_INVALID_PARAMETER_VALUE,
> + "x-igd-gms", "0~0x40 or 0xf0~0xfe");
> + }
> + }
> +
> + return ret;
> +}
> +
> #define IGD_GGC_MMIO_OFFSET 0x108040
> #define IGD_BDSM_MMIO_OFFSET 0x1080C0
>
> @@ -573,24 +611,9 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice
> *vdev, Error **errp)
> * 32MiB. This option should only be used when the desired size cannot be
> * set from DVMT Pre-Allocated option in host BIOS.
> */
> - if (vdev->igd_gms) {
> - if (gen < 8) {
> - if (vdev->igd_gms <= 0x10) {
> - gmch &= ~(IGD_GMCH_GEN6_GMS_MASK << IGD_GMCH_GEN6_GMS_SHIFT);
> - gmch |= vdev->igd_gms << IGD_GMCH_GEN6_GMS_SHIFT;
> - } else {
> - error_report(QERR_INVALID_PARAMETER_VALUE,
> - "x-igd-gms", "0~0x10");
> - }
> - } else {
> - if (vdev->igd_gms <= 0x40) {
> - gmch &= ~(IGD_GMCH_GEN8_GMS_MASK << IGD_GMCH_GEN8_GMS_SHIFT);
> - gmch |= vdev->igd_gms << IGD_GMCH_GEN8_GMS_SHIFT;
> - } else {
> - error_report(QERR_INVALID_PARAMETER_VALUE,
> - "x-igd-gms", "0~0x40");
> - }
> - }
> + if (vdev->igd_gms &&
> + !vfio_pci_igd_override_gms(gen, vdev->igd_gms, &gmch)) {
> + return false;
> }
>
> gms_size = igd_stolen_memory_size(gen, gmch);
--
Kind regards,
Corvin
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