>-----Original Message-----
>From: Jason Wang <jasow...@redhat.com>
>Subject: Re: [PATCH v3 12/17] intel_iommu: Add support for PASID-based
>device IOTLB invalidation
>
>On Wed, Sep 11, 2024 at 1:27 PM Zhenzhong Duan
><zhenzhong.d...@intel.com> wrote:
>>
>> From: Clément Mathieu--Drif <clement.mathieu--d...@eviden.com>
>>
>> Signed-off-by: Clément Mathieu--Drif <clement.mathieu--d...@eviden.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
>> ---
>> hw/i386/intel_iommu_internal.h | 11 ++++++++
>> hw/i386/intel_iommu.c | 50
>++++++++++++++++++++++++++++++++++
>> 2 files changed, 61 insertions(+)
>>
>> diff --git a/hw/i386/intel_iommu_internal.h
>b/hw/i386/intel_iommu_internal.h
>> index 4f2c3a9350..52bdbf3bc5 100644
>> --- a/hw/i386/intel_iommu_internal.h
>> +++ b/hw/i386/intel_iommu_internal.h
>> @@ -375,6 +375,7 @@ typedef union VTDInvDesc VTDInvDesc;
>> #define VTD_INV_DESC_WAIT 0x5 /* Invalidation Wait Descriptor
>*/
>> #define VTD_INV_DESC_PIOTLB 0x6 /* PASID-IOTLB Invalidate Desc
>*/
>> #define VTD_INV_DESC_PC 0x7 /* PASID-cache Invalidate Desc
>> */
>> +#define VTD_INV_DESC_DEV_PIOTLB 0x8 /* PASID-based-DIOTLB
>inv_desc*/
>> #define VTD_INV_DESC_NONE 0 /* Not an Invalidate Descriptor
>*/
>>
>> /* Masks for Invalidation Wait Descriptor*/
>> @@ -413,6 +414,16 @@ typedef union VTDInvDesc VTDInvDesc;
>> #define VTD_INV_DESC_DEVICE_IOTLB_RSVD_HI 0xffeULL
>> #define VTD_INV_DESC_DEVICE_IOTLB_RSVD_LO 0xffff0000ffe0fff8
>>
>> +/* Mask for PASID Device IOTLB Invalidate Descriptor */
>> +#define VTD_INV_DESC_PASID_DEVICE_IOTLB_ADDR(val) ((val) & \
>> + 0xfffffffffffff000ULL)
>> +#define VTD_INV_DESC_PASID_DEVICE_IOTLB_SIZE(val) ((val >> 11) & 0x1)
>> +#define VTD_INV_DESC_PASID_DEVICE_IOTLB_GLOBAL(val) ((val) & 0x1)
>> +#define VTD_INV_DESC_PASID_DEVICE_IOTLB_SID(val) (((val) >> 16) &
>0xffffULL)
>> +#define VTD_INV_DESC_PASID_DEVICE_IOTLB_PASID(val) ((val >> 32) &
>0xfffffULL)
>> +#define VTD_INV_DESC_PASID_DEVICE_IOTLB_RSVD_HI 0x7feULL
>> +#define VTD_INV_DESC_PASID_DEVICE_IOTLB_RSVD_LO
>0xfff000000000f000ULL
>> +
>> /* Rsvd field masks for spte */
>> #define VTD_SPTE_SNP 0x800ULL
>>
>> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
>> index d28c862598..4cf56924e1 100644
>> --- a/hw/i386/intel_iommu.c
>> +++ b/hw/i386/intel_iommu.c
>> @@ -3017,6 +3017,49 @@ static void
>do_invalidate_device_tlb(VTDAddressSpace *vtd_dev_as,
>> memory_region_notify_iommu(&vtd_dev_as->iommu, 0, event);
>> }
>>
>> +static bool vtd_process_device_piotlb_desc(IntelIOMMUState *s,
>> + VTDInvDesc *inv_desc)
>> +{
>> + uint16_t sid;
>> + VTDAddressSpace *vtd_dev_as;
>> + bool size;
>> + bool global;
>> + hwaddr addr;
>> + uint32_t pasid;
>> +
>> + if ((inv_desc->hi & VTD_INV_DESC_PASID_DEVICE_IOTLB_RSVD_HI) ||
>> + (inv_desc->lo & VTD_INV_DESC_PASID_DEVICE_IOTLB_RSVD_LO)) {
>> + error_report_once("%s: invalid pasid-based dev iotlb inv desc:"
>> + "hi=%"PRIx64 "(reserved nonzero)",
>> + __func__, inv_desc->hi);
>> + return false;
>> + }
>> +
>> + global = VTD_INV_DESC_PASID_DEVICE_IOTLB_GLOBAL(inv_desc->hi);
>> + size = VTD_INV_DESC_PASID_DEVICE_IOTLB_SIZE(inv_desc->hi);
>> + addr = VTD_INV_DESC_PASID_DEVICE_IOTLB_ADDR(inv_desc->hi);
>> + sid = VTD_INV_DESC_PASID_DEVICE_IOTLB_SID(inv_desc->lo);
>> + if (global) {
>> + QLIST_FOREACH(vtd_dev_as, &s->vtd_as_with_notifiers, next) {
>> + if ((vtd_dev_as->pasid != PCI_NO_PASID) &&
>> + (PCI_BUILD_BDF(pci_bus_num(vtd_dev_as->bus),
>> + vtd_dev_as->devfn) == sid)) {
>> + do_invalidate_device_tlb(vtd_dev_as, size, addr);
>> + }
>> + }
>> + } else {
>> + pasid = VTD_INV_DESC_PASID_DEVICE_IOTLB_PASID(inv_desc->lo);
>> + vtd_dev_as = vtd_get_as_by_sid_and_pasid(s, sid, pasid);
>> + if (!vtd_dev_as) {
>> + return true;
>> + }
>> +
>> + do_invalidate_device_tlb(vtd_dev_as, size, addr);
>
>Question:
>
>I wonder if current vhost (which has a device IOTLB abstraction via
>virtio-pci) can work with this (PASID based IOTLB invalidation)
Currently, it depends on if caching-mode is on. If it's off, vhost works. E.g.:
-device
intel-iommu,caching-mode=off,dma-drain=on,device-iotlb=on,x-scalable-mode=on
-netdev tap,id=tap0,vhost=on,script=/etc/qemu-ifup
-device virtio-net-pci,netdev=tap0,bus=root0,iommu_platform=on,ats=on
It doesn't work currently when caching-mode is on.
Reason is linux kernel has an optimization to send only piotlb invalidation,
no device-piotlb invalidation is sent. But I heard from Yi the optimization
will be dropped, then it will work too when caching-mode is on.
Thanks
Zhenzhong
