From 37f05a59e8695df3d1206e7100190e48ec0af847 Mon Sep 17 00:00:00 2001 From: Tomita Moeko Date: Fri, 6 Dec 2024 20:27:48 +0800 Subject: [PATCH] vfio/igd: add x-igd-gms option back to set DSM region size for guest MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit DSM region is likely to store framebuffer in Windows, a small DSM region may cause display issues (e.g. half of the screen is black). Since 971ca22f041b ("vfio/igd: don't set stolen memory size to zero"), the x-igd-gms option was functionally removed, QEMU uses host's original value, which is determined by DVMT Pre-Allocated option in Intel FSP of host bios. However, some vendors do not expose this config item to users. In such cases, x-igd-gms option can be used to manually set the data stolen memory size for guest. So this commit brings this option back, keeping its old behavior. When it is not specified, QEMU uses host's value. When DVMT Pre-Allocated option is available in host BIOS, user should set DSM region size there instead of using x-igd-gms option. Signed-off-by: Tomita Moeko Reviewed-by: Alex Williamson Link: https://lore.kernel.org/r/20241206122749.9893-11-tomitamoeko@gmail.com Signed-off-by: Cédric Le Goater --- hw/vfio/igd.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c index c15a14e445..0740a5dd8c 100644 --- a/hw/vfio/igd.c +++ b/hw/vfio/igd.c @@ -14,6 +14,7 @@ #include "qemu/units.h" #include "qemu/error-report.h" #include "qapi/error.h" +#include "qapi/qmp/qerror.h" #include "hw/hw.h" #include "hw/nvram/fw_cfg.h" #include "pci.h" @@ -722,6 +723,31 @@ void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr) QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next); + /* + * Allow user to override dsm size using x-igd-gms option, in multiples of + * 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"); + } + } + } + ggms_size = igd_gtt_memory_size(gen, gmch); gms_size = igd_stolen_memory_size(gen, gmch); -- 2.30.2