>-----Original Message----- >From: CLEMENT MATHIEU--DRIF <clement.mathieu--d...@eviden.com> >Subject: Re: [PATCH v2 03/17] intel_iommu: Add a placeholder variable for >scalable modern mode > > > >On 13/08/2024 04:20, Duan, Zhenzhong wrote: >> Caution: External email. Do not open attachments or click links, unless this >email comes from a known sender and you know the content is safe. >> >> >>> -----Original Message----- >>> From: CLEMENT MATHIEU--DRIF <clement.mathieu--d...@eviden.com> >>> Subject: Re: [PATCH v2 03/17] intel_iommu: Add a placeholder variable >for >>> scalable modern mode >>> >>> >>> >>> On 08/08/2024 14:31, Duan, Zhenzhong wrote: >>>> Caution: External email. Do not open attachments or click links, >>>> unless this email comes from a known sender and you know the content >>>> is safe. >>>> >>>> >>>> On 8/6/2024 2:35 PM, CLEMENT MATHIEU--DRIF wrote: >>>>> On 05/08/2024 08:27, Zhenzhong Duan wrote: >>>>>> Caution: External email. Do not open attachments or click links, >>>>>> unless this email comes from a known sender and you know the >content >>>>>> is safe. >>>>>> >>>>>> >>>>>> 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 | 12 +++++++++--- >>>>>> 2 files changed, 10 insertions(+), 3 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..c1382a5651 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, >>>>>> @@ -4262,9 +4268,9 @@ 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)) { >>>>>> + (s->aw_bits != VTD_HOST_AW_48BIT) && >>>>>> + !s->scalable_modern) { >>>>> Why does scalable_modern allow to use a value other than 39 or 48? >>>>> Is it safe? >>>> The check for scalable_modern is in patch14: >>>> >>>> if ((s->aw_bits != VTD_HOST_AW_48BIT) && s->scalable_modern) { >>>> >>>> error_setg(errp, "Supported values for aw-bits are: %d", >>>> VTD_HOST_AW_48BIT); >>>> >>>> return false; >>>> >>>> } >>>> >>>> Let me know if you prefer to move it in this patch. >>> Yes, you are right, it would be better to move the check here. >>> >>> But I think the first check should also fail even when scalable_modern >>> is enabled because values other than 39 and 48 are not supported at all, >>> whatever the mode. >>> Then, we should check if the value is valid for scalable_modern mode. >> Right, I wrote that way with a possible plan to support >VTD_HOST_AW_52BIT. >52 or 57?
Sorry, I mean 57. >> What about this: >> >This condition traps (non-scalable) legacy mode as well. I think we >should change the error message to make it clear >Something like this: "Legacy and non-modern scalable modes: supported >values for aw-bit are ..." >Or we could make the error message conditional. Yes, I'd like to be conditional, like: if ((s->aw_bits != VTD_HOST_AW_39BIT) && (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", VTD_HOST_AW_39BIT, VTD_HOST_AW_48BIT); return false; } >> if ((s->aw_bits != VTD_HOST_AW_39BIT) && >> (s->aw_bits != VTD_HOST_AW_48BIT) && >> !s->scalable_modern) { >> error_setg(errp, "Scalable legacy mode: supported values for aw-bits >are: %d, %d", >> 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; >> } > > >> >> Thanks >> Zhenzhong