>-----Original Message-----
>From: Cédric Le Goater <[email protected]>
>Subject: Re: [PATCH v7 13/23] intel_iommu: Bind/unbind guest page table to
>host
>
>On 10/24/25 10:43, Zhenzhong Duan wrote:
>> This captures the guest PASID table entry modifications and propagates
>> the changes to host to attach a hwpt with type determined per guest
>IOMMU
>> PGTT configuration.
>>
>> When PGTT=PT, attach PASID_0 to a second stage HWPT(GPA->HPA).
>> When PGTT=FST, attach PASID_0 to nested HWPT with nesting parent HWPT
>> coming from VFIO.
>>
>> Co-Authored-by: Yi Liu <[email protected]>
>> Signed-off-by: Yi Liu <[email protected]>
>> Signed-off-by: Yi Sun <[email protected]>
>> Signed-off-by: Zhenzhong Duan <[email protected]>
>> ---
>> include/hw/i386/intel_iommu.h | 1 +
>> hw/i386/intel_iommu.c | 150
>+++++++++++++++++++++++++++++++++-
>> hw/i386/trace-events | 3 +
>> 3 files changed, 151 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/hw/i386/intel_iommu.h
>b/include/hw/i386/intel_iommu.h
>> index 3758ac239c..b5f8a9fc29 100644
>> --- a/include/hw/i386/intel_iommu.h
>> +++ b/include/hw/i386/intel_iommu.h
>> @@ -104,6 +104,7 @@ struct VTDAddressSpace {
>> PCIBus *bus;
>> uint8_t devfn;
>> uint32_t pasid;
>> + uint32_t fs_hwpt;
>> AddressSpace as;
>> IOMMUMemoryRegion iommu;
>> MemoryRegion root; /* The root container of the
>device */
>> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
>> index 871e6aad19..3789a36147 100644
>> --- a/hw/i386/intel_iommu.c
>> +++ b/hw/i386/intel_iommu.c
>> @@ -20,6 +20,7 @@
>> */
>>
>> #include "qemu/osdep.h"
>> +#include CONFIG_DEVICES /* CONFIG_IOMMUFD */
>> #include "qemu/error-report.h"
>> #include "qemu/main-loop.h"
>> #include "qapi/error.h"
>> @@ -42,6 +43,9 @@
>> #include "migration/vmstate.h"
>> #include "trace.h"
>> #include "system/iommufd.h"
>> +#ifdef CONFIG_IOMMUFD
>> +#include <linux/iommufd.h>
>> +#endif
>>
>> /* context entry operations */
>> #define PASID_0 0
>> @@ -87,6 +91,7 @@ struct vtd_iotlb_key {
>>
>> static void vtd_address_space_refresh_all(IntelIOMMUState *s);
>> static void vtd_address_space_unmap(VTDAddressSpace *as,
>IOMMUNotifier *n);
>> +static int vtd_bind_guest_pasid(VTDAddressSpace *vtd_as, Error **errp);
>>
>> static void vtd_pasid_cache_reset_locked(IntelIOMMUState *s)
>> {
>> @@ -98,7 +103,11 @@ static void
>vtd_pasid_cache_reset_locked(IntelIOMMUState *s)
>> g_hash_table_iter_init(&as_it, s->vtd_address_spaces);
>> while (g_hash_table_iter_next(&as_it, NULL, (void **)&vtd_as)) {
>> VTDPASIDCacheEntry *pc_entry =
>&vtd_as->pasid_cache_entry;
>> - pc_entry->valid = false;
>> + if (pc_entry->valid) {
>> + pc_entry->valid = false;
>> + /* It's fatal to get failure during reset */
>> + vtd_bind_guest_pasid(vtd_as, &error_fatal);
>> + }
>> }
>> }
>>
>> @@ -2380,6 +2389,128 @@ static void
>vtd_context_global_invalidate(IntelIOMMUState *s)
>> vtd_iommu_replay_all(s);
>> }
>>
>> +#ifdef CONFIG_IOMMUFD
>> +static int vtd_create_fs_hwpt(HostIOMMUDeviceIOMMUFD *idev,
>> + VTDPASIDEntry *pe, uint32_t
>*fs_hwpt,
>> + Error **errp)
>
>Returning a bool is better. Same for the routines below.
We will need the returned error code to determine the fault event to inject to
guest
in future fault event series.
>
>> +{
>> + struct iommu_hwpt_vtd_s1 vtd = {};
>> +
>> + vtd.flags = (VTD_SM_PASID_ENTRY_SRE_BIT(pe) ?
>IOMMU_VTD_S1_SRE : 0) |
>> + (VTD_SM_PASID_ENTRY_WPE_BIT(pe) ?
>IOMMU_VTD_S1_WPE : 0) |
>> + (VTD_SM_PASID_ENTRY_EAFE_BIT(pe) ?
>IOMMU_VTD_S1_EAFE : 0);
>> + vtd.addr_width = vtd_pe_get_fs_aw(pe);
>> + vtd.pgtbl_addr = (uint64_t)vtd_pe_get_fspt_base(pe);
>> +
>> + return !iommufd_backend_alloc_hwpt(idev->iommufd, idev->devid,
>> + idev->hwpt_id, 0,
>IOMMU_HWPT_DATA_VTD_S1,
>> + sizeof(vtd), &vtd, fs_hwpt,
>errp);
>> +}
>> +
>> +static void vtd_destroy_old_fs_hwpt(HostIOMMUDeviceIOMMUFD *idev,
>> + VTDAddressSpace *vtd_as)
>> +{
>> + if (!vtd_as->fs_hwpt) {
>> + return;
>> + }
>> + iommufd_backend_free_id(idev->iommufd, vtd_as->fs_hwpt);
>> + vtd_as->fs_hwpt = 0;
>> +}
>> +
>> +static int vtd_device_attach_iommufd(VTDHostIOMMUDevice *vtd_hiod,
>> + VTDAddressSpace *vtd_as,
>Error **errp)
>> +{
>> + HostIOMMUDeviceIOMMUFD *idev =
>HOST_IOMMU_DEVICE_IOMMUFD(vtd_hiod->hiod);
>> + VTDPASIDEntry *pe = &vtd_as->pasid_cache_entry.pasid_entry;
>> + uint32_t hwpt_id;
>> + bool ret;
>> +
>> + /*
>> + * We can get here only if flts=on, the supported PGTT is FST and PT.
>> + * Catch invalid PGTT when processing invalidation request to avoid
>> + * attaching to wrong hwpt.
>> + */
>> + if (!vtd_pe_pgtt_is_fst(pe) && !vtd_pe_pgtt_is_pt(pe)) {
>> + error_setg(errp, "Invalid PGTT type");
>> + return -EINVAL;
>> + }
>> +
>> + if (vtd_pe_pgtt_is_pt(pe)) {
>> + hwpt_id = idev->hwpt_id;
>> + } else if (vtd_create_fs_hwpt(idev, pe, &hwpt_id, errp)) {
>> + return -EINVAL;
>> + }
>> +
>> + ret = host_iommu_device_iommufd_attach_hwpt(idev, hwpt_id,
>errp);
>> + trace_vtd_device_attach_hwpt(idev->devid, vtd_as->pasid,
>hwpt_id, !ret);
>> + if (ret) {
>> + /* Destroy old fs_hwpt if it's a replacement */
>> + vtd_destroy_old_fs_hwpt(idev, vtd_as);
>> + if (vtd_pe_pgtt_is_fst(pe)) {
>> + vtd_as->fs_hwpt = hwpt_id;
>> + }
>> + } else if (vtd_pe_pgtt_is_fst(pe)) {
>> + iommufd_backend_free_id(idev->iommufd, hwpt_id);
>> + }
>> +
>> + return !ret;
>> +}
>> +
>> +static int vtd_device_detach_iommufd(VTDHostIOMMUDevice *vtd_hiod,
>> + VTDAddressSpace *vtd_as,
>Error **errp)
>> +{
>> + HostIOMMUDeviceIOMMUFD *idev =
>HOST_IOMMU_DEVICE_IOMMUFD(vtd_hiod->hiod);
>> + IntelIOMMUState *s = vtd_as->iommu_state;
>> + uint32_t pasid = vtd_as->pasid;
>> + bool ret;
>> +
>> + if (s->dmar_enabled && s->root_scalable) {
>> + ret = host_iommu_device_iommufd_detach_hwpt(idev, errp);
>> + trace_vtd_device_detach_hwpt(idev->devid, pasid, !ret);
>> + } else {
>> + /*
>> + * If DMAR remapping is disabled or guest switches to legacy
>mode,
>> + * we fallback to the default HWPT which contains shadow page
>table.
>> + * So guest DMA could still work.
>> + */
>> + ret = host_iommu_device_iommufd_attach_hwpt(idev,
>idev->hwpt_id, errp);
>> + trace_vtd_device_reattach_def_hwpt(idev->devid, pasid,
>idev->hwpt_id,
>> + !ret);
>> + }
>> +
>> + if (ret) {
>> + vtd_destroy_old_fs_hwpt(idev, vtd_as);
>> + }
>> +
>> + return !ret;
>> +}
>> +
>> +static int vtd_bind_guest_pasid(VTDAddressSpace *vtd_as, Error **errp)
>> +{
>> + VTDPASIDCacheEntry *pc_entry = &vtd_as->pasid_cache_entry;
>> + VTDHostIOMMUDevice *vtd_hiod = vtd_find_hiod_iommufd(vtd_as);
>> + int ret;
>> +
>> + /* Ignore emulated device or legacy VFIO backed device */
>> + if (!vtd_hiod) {
>> + return 0;
>> + }
>> +
>> + if (pc_entry->valid) {
>> + ret = vtd_device_attach_iommufd(vtd_hiod, vtd_as, errp);
>> + } else {
>> + ret = vtd_device_detach_iommufd(vtd_hiod, vtd_as, errp);
>> + }
>> +
>> + return ret;
>> +}
>> +#else
>> +static int vtd_bind_guest_pasid(VTDAddressSpace *vtd_as, Error **errp)
>> +{
>> + return 0;
>> +}
>> +#endif
>> +
>> /* Do a context-cache device-selective invalidation.
>> * @func_mask: FM field after shifting
>> */
>> @@ -3134,6 +3265,8 @@ static void
>vtd_pasid_cache_sync_locked(gpointer key, gpointer value,
>> VTDPASIDEntry pe;
>> IOMMUNotifier *n;
>> uint16_t did;
>> + const char *err_prefix;
>
>Setting this prefix looks a bit fragile. May be add a default value here.
OK, like:
const char *err_prefix = "Attaching to HWPT failed: ";
Thanks
Zhenzhong
