Hi Zhenzhong,
On 10/24/25 10:43 AM, 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)
> +{
> + 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);
see comments below
> +}
> +
> +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.
is FST or 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");
print the wrong PGTT value?
> + 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);
why !ret in the trace? I think e chose to return true on success for
host_iommu_device_iommufd_attach_hwpt()
. Let's keep this consistent otherwise we end up not knowning what is
the success value.
> + 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;
argh. Eventually it is difficult to follow ;-)
> +}
> +
> +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);
> same
> + } 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);
same
> + }
> +
> + 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);
return directly
> + } else {
remove the else and return directly?
> + 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;
> + Error *local_err = NULL;
>
> if (vtd_dev_get_pe_from_pasid(vtd_as, &pe)) {
> if (!pc_entry->valid) {
> @@ -3154,7 +3287,9 @@ static void vtd_pasid_cache_sync_locked(gpointer key,
> gpointer value,
> vtd_address_space_unmap(vtd_as, n);
> }
> vtd_switch_address_space(vtd_as);
> - return;
> +
> + err_prefix = "Detaching from HWPT failed: ";
> + goto do_bind_unbind;
> }
>
> /*
> @@ -3182,12 +3317,21 @@ static void vtd_pasid_cache_sync_locked(gpointer key,
> gpointer value,
> if (!pc_entry->valid) {
> pc_entry->pasid_entry = pe;
> pc_entry->valid = true;
> - } else if (!vtd_pasid_entry_compare(&pe, &pc_entry->pasid_entry)) {
> + err_prefix = "Attaching to HWPT failed: ";
> + } else if (vtd_pasid_entry_compare(&pe, &pc_entry->pasid_entry)) {
> + err_prefix = "Replacing HWPT attachment failed: ";
> + } else {
> return;
> }
>
> vtd_switch_address_space(vtd_as);
> vtd_address_space_sync(vtd_as);
> +
> +do_bind_unbind:
> + /* TODO: Fault event injection into guest, report error to QEMU for now
> */
> + if (vtd_bind_guest_pasid(vtd_as, &local_err)) {
> + error_reportf_err(local_err, "%s", err_prefix);
> + }
> }
>
> static void vtd_pasid_cache_sync(IntelIOMMUState *s, VTDPASIDCacheInfo
> *pc_info)
> diff --git a/hw/i386/trace-events b/hw/i386/trace-events
> index b704f4f90c..5a3ee1cf64 100644
> --- a/hw/i386/trace-events
> +++ b/hw/i386/trace-events
> @@ -73,6 +73,9 @@ vtd_warn_invalid_qi_tail(uint16_t tail) "tail 0x%"PRIx16
> vtd_warn_ir_vector(uint16_t sid, int index, int vec, int target) "sid
> 0x%"PRIx16" index %d vec %d (should be: %d)"
> vtd_warn_ir_trigger(uint16_t sid, int index, int trig, int target) "sid
> 0x%"PRIx16" index %d trigger %d (should be: %d)"
> vtd_reset_exit(void) ""
> +vtd_device_attach_hwpt(uint32_t dev_id, uint32_t pasid, uint32_t hwpt_id,
> int ret) "dev_id %d pasid %d hwpt_id %d, ret: %d"
> +vtd_device_detach_hwpt(uint32_t dev_id, uint32_t pasid, int ret) "dev_id %d
> pasid %d ret: %d"
> +vtd_device_reattach_def_hwpt(uint32_t dev_id, uint32_t pasid, uint32_t
> hwpt_id, int ret) "dev_id %d pasid %d hwpt_id %d, ret: %d"
>
> # amd_iommu.c
> amdvi_evntlog_fail(uint64_t addr, uint32_t head) "error: fail to write at
> addr 0x%"PRIx64" + offset 0x%"PRIx32
Eric
