On 11/09/2024 07:22, Zhenzhong Duan wrote:
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> Add an new element scalable_mode in IntelIOMMUState to mark scalable
> modern mode, this element will be exposed as an intel_iommu property
> finally.
>
> For now, it's only a placehholder and used for address width
> compatibility check and block host device passthrough until nesting
> is supported.
>
> Signed-off-by: Yi Liu <yi.l....@intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
> ---
> include/hw/i386/intel_iommu.h | 1 +
> hw/i386/intel_iommu.c | 22 ++++++++++++++++++----
> 2 files changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> index 1eb05c29fc..788ed42477 100644
> --- a/include/hw/i386/intel_iommu.h
> +++ b/include/hw/i386/intel_iommu.h
> @@ -262,6 +262,7 @@ struct IntelIOMMUState {
>
> bool caching_mode; /* RO - is cap CM enabled? */
> bool scalable_mode; /* RO - is Scalable Mode supported? */
> + bool scalable_modern; /* RO - is modern SM supported? */
> bool snoop_control; /* RO - is SNP filed supported? */
>
> dma_addr_t root; /* Current root table pointer */
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index e3465fc27d..57c24f67b4 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -3872,7 +3872,13 @@ static bool vtd_check_hiod(IntelIOMMUState *s,
> HostIOMMUDevice *hiod,
> return false;
> }
>
> - return true;
> + if (!s->scalable_modern) {
> + /* All checks requested by VTD non-modern mode pass */
> + return true;
> + }
> +
> + error_setg(errp, "host device is unsupported in scalable modern mode
> yet");
> + return false;
> }
>
> static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
> @@ -4262,14 +4268,22 @@ static bool vtd_decide_config(IntelIOMMUState *s,
> Error **errp)
> }
> }
>
> - /* Currently only address widths supported are 39 and 48 bits */
> if ((s->aw_bits != VTD_HOST_AW_39BIT) &&
> - (s->aw_bits != VTD_HOST_AW_48BIT)) {
> - error_setg(errp, "Supported values for aw-bits are: %d, %d",
> + (s->aw_bits != VTD_HOST_AW_48BIT) &&
> + !s->scalable_modern) {
> + error_setg(errp, "%s mode: supported values for aw-bits are: %d, %d",
> + s->scalable_mode ? "Scalable legacy" : "Legacy",
I think we should be consistent in the way we name things.
s/Scalable legacy/Scalable
> VTD_HOST_AW_39BIT, VTD_HOST_AW_48BIT);
> return false;
> }
>
> + if ((s->aw_bits != VTD_HOST_AW_48BIT) && s->scalable_modern) {
> + error_setg(errp,
> + "Scalable modern mode: supported values for aw-bits is:
> %d",
> + VTD_HOST_AW_48BIT);
> + return false;
> + }
> +
In both conditions, I would rather test the mode first to make the
intention clearer.
For instance,
(s->aw_bits != VTD_HOST_AW_48BIT) && s->scalable_modern
would become
s->scalable_modern && (s->aw_bits != VTD_HOST_AW_48BIT)
Apart from these minor comments, the patch looks good to me
> if (s->scalable_mode && !s->dma_drain) {
> error_setg(errp, "Need to set dma_drain for scalable mode");
> return false;
> --
> 2.34.1
>
