Hi Shammer, On 6/1/26 1:42 PM, Shameer Kolothum wrote: > From: Nicolin Chen <[email protected]> I would disambiguate the title a little bit: Use mmap'd host VINTF page0 for virtual VINTF page0
Also in previous patch titles you could emphase the mmap'd page is the host one in a similar way. > > Install the mmap'd vintf_page0 region as a RAM-device MemoryRegion at > guest MMIO offset 0x30000 (the VINTF Page 0 aperture) when VINTF is > enabled, and remove it on VINTF disable. This eliminates QEMU > trapping for hot-path CONS/PROD index updates via the VINTF aperture. > > After this patch, the two VCMDQ Page 0 apertures use different > access paths: the direct aperture (0x10000) remains QEMU-trapped, > while the VINTF aperture (0x30000) is a guest-direct RAM mapping. > > The direct aperture is intentionally kept trapped (not aliased to > the VINTF mmap) so that writes to an unallocated VCMDQ remain > well-defined. The CMDQV architecture allows software to program a > VCMDQ through the direct aperture without first allocating it to a > VINTF; aliasing would route those writes to unallocated logical > slots in the VINTF page, where the hardware silently drops them. > > Signed-off-by: Nicolin Chen <[email protected]> > Co-developed-by: Shameer Kolothum <[email protected]> > Signed-off-by: Shameer Kolothum <[email protected]> > --- > hw/arm/tegra241-cmdqv.h | 1 + > hw/arm/tegra241-cmdqv.c | 36 ++++++++++++++++++++++++++++++++++++ > 2 files changed, 37 insertions(+) > > diff --git a/hw/arm/tegra241-cmdqv.h b/hw/arm/tegra241-cmdqv.h > index 84499b840d..01cd6af97d 100644 > --- a/hw/arm/tegra241-cmdqv.h > +++ b/hw/arm/tegra241-cmdqv.h > @@ -49,6 +49,7 @@ typedef struct Tegra241CMDQV { > IOMMUFDVeventq *veventq; > IOMMUFDHWqueue *vcmdq[TEGRA241_CMDQV_MAX_CMDQ]; > void *vintf_page0; > + MemoryRegion *mr_vintf_page0; > > /* CMDQ-V Config page register cache */ > uint32_t config; > diff --git a/hw/arm/tegra241-cmdqv.c b/hw/arm/tegra241-cmdqv.c > index dce7089697..cdd4fa4f1a 100644 > --- a/hw/arm/tegra241-cmdqv.c > +++ b/hw/arm/tegra241-cmdqv.c > @@ -18,6 +18,40 @@ > #include "tegra241-cmdqv.h" > #include "trace.h" > > +static void tegra241_cmdqv_guest_unmap_vintf_page0(Tegra241CMDQV *cmdqv) > +{ > + if (!cmdqv->mr_vintf_page0) { > + return; > + } > + > + memory_region_del_subregion(&cmdqv->mmio_cmdqv, cmdqv->mr_vintf_page0); > + object_unparent(OBJECT(cmdqv->mr_vintf_page0)); > + g_free(cmdqv->mr_vintf_page0); > + cmdqv->mr_vintf_page0 = NULL; > +} > + > +static void tegra241_cmdqv_guest_map_vintf_page0(Tegra241CMDQV *cmdqv) > +{ > + char *name; > + > + if (cmdqv->mr_vintf_page0) { > + return; > + } > + > + name = g_strdup_printf("%s vintf-page0", > + memory_region_name(&cmdqv->mmio_cmdqv)); > + cmdqv->mr_vintf_page0 = g_malloc0(sizeof(*cmdqv->mr_vintf_page0)); > + memory_region_init_ram_device_ptr(cmdqv->mr_vintf_page0, > + > memory_region_owner(&cmdqv->mmio_cmdqv), > + name, VINTF_PAGE_SIZE, > + cmdqv->vintf_page0); > + memory_region_set_skip_iommu_map(cmdqv->mr_vintf_page0, true); > + memory_region_add_subregion_overlap(&cmdqv->mmio_cmdqv, > + CMDQV_VINTF_PAGE0_BASE, > + cmdqv->mr_vintf_page0, 1); > + g_free(name); > +} > + > static void tegra241_cmdqv_free_vcmdq(Tegra241CMDQV *cmdqv, int index) > { > IOMMUFDViommu *viommu = cmdqv->s_accel->viommu; > @@ -445,6 +479,7 @@ static void > tegra241_cmdqv_config_vintf_write(Tegra241CMDQV *cmdqv, > if (value & R_VINTF0_CONFIG_ENABLE_MASK) { > if (tegra241_cmdqv_mmap_vintf_page0(cmdqv, errp)) { > cmdqv->vintf_status |= R_VINTF0_STATUS_ENABLE_OK_MASK; > + tegra241_cmdqv_guest_map_vintf_page0(cmdqv); don't you want to do that only after the tegra241_cmdqv_setup_all_vcmdq()? > /* > * VCMDQs whose BASE was programmed before VINTF was > * enabled need their hw_queue allocated now. > @@ -452,6 +487,7 @@ static void > tegra241_cmdqv_config_vintf_write(Tegra241CMDQV *cmdqv, > tegra241_cmdqv_setup_all_vcmdq(cmdqv, errp); > } > } else { > + tegra241_cmdqv_guest_unmap_vintf_page0(cmdqv); > tegra241_cmdqv_free_all_vcmdq(cmdqv); > tegra241_cmdqv_munmap_vintf_page0(cmdqv, errp); > cmdqv->vintf_status &= ~R_VINTF0_STATUS_ENABLE_OK_MASK; Thanks Eric
