Re: [PATCH 2/8] iommu/vt-d: Add entry_sync support for PASID entry updates

[Baolu Lu]

On 3/9/26 21:41, Jason Gunthorpe wrote:
> On Mon, Mar 09, 2026 at 02:06:42PM +0800, Lu Baolu wrote:
> > +static void intel_pasid_get_used(const u128 *entry, u128 *used)
> > +{
> > +	struct pasid_entry *pe = (struct pasid_entry *)entry;
> > +	struct pasid_entry *ue = (struct pasid_entry *)used;
> > +	u16 pgtt;
> > +
> > +	/* Initialize used bits to 0. */
> > +	memset(ue, 0, sizeof(*ue));
> > +
> > +	/* Present bit always matters. */
> > +	ue->val[0] |= PASID_PTE_PRESENT;
> > +
> > +	/* Nothing more for non-present entries. */
> > +	if (!(pe->val[0] & PASID_PTE_PRESENT))
> > +		return;
> > +
> > +	pgtt = pasid_pte_get_pgtt(pe);
> > +	switch (pgtt) {
> > +	case PASID_ENTRY_PGTT_FL_ONLY:
> > +		/* AW, PGTT */
> > +		ue->val[0] |= GENMASK_ULL(4, 2) | GENMASK_ULL(8, 6);
> > +		/* DID, PWSNP, PGSNP */
> > +		ue->val[1] |= GENMASK_ULL(24, 23) | GENMASK_ULL(15, 0);
> > +		/* FSPTPTR, FSPM */
> > +		ue->val[2] |= GENMASK_ULL(63, 12) | GENMASK_ULL(3, 2);
> This would be an excellent time to properly add these constants 🙁
>
> /* 9.6 Scalable-Mode PASID Table Entry */
> #define SM_PASID0_P		BIT_U64(0)
> #define SM_PASID0_FPD		BIT_U64(1)
> #define SM_PASID0_AW		GENMASK_U64(4, 2)
> #define SM_PASID0_SSEE		BIT_U64(5)
> #define SM_PASID0_PGTT		GENMASK_U64(8, 6)
> #define SM_PASID0_SSADE		BIT_U64(9)
> #define SM_PASID0_SSPTPTR	GENMASK_U64(63, 12)
>
> #define SM_PASID1_DID		GENMASK_U64(15, 0)
> #define SM_PASID1_PWSNP		BIT_U64(23)
> #define SM_PASID1_PGSNP		BIT_U64(24)
> #define SM_PASID1_CD		BIT_U64(25)
> #define SM_PASID1_EMTE		BIT_U64(26)
> #define SM_PASID1_PAT		GENMASK_U64(63, 32)
>
> #define SM_PASID2_SRE		BIT_U64(0)
> #define SM_PASID2_ERE		BIT_U64(1)
> #define SM_PASID2_FSPM		GENMASK_U64(3, 2)
> #define SM_PASID2_WPE		BIT_U64(4)
> #define SM_PASID2_NXE		BIT_U64(5)
> #define SM_PASID2_SMEP		BIT_U64(6)
> #define SM_PASID2_EAFE		BIT_U64(7)
> #define SM_PASID2_FSPTPTR	GENMASK_U64(63, 12)

Yeah, code updated like this,

drivers/iommu/intel/pasid.h:

/* 9.6 Scalable-Mode PASID Table Entry */
#define SM_PASID0_P             BIT_U64(0)
#define SM_PASID0_FPD           BIT_U64(1)
#define SM_PASID0_AW            GENMASK_U64(4, 2)
#define SM_PASID0_PGTT          GENMASK_U64(8, 6)
#define SM_PASID0_SSADE         BIT_U64(9)
#define SM_PASID0_SSPTPTR       GENMASK_U64(63, 12)

#define SM_PASID1_DID           GENMASK_U64(15, 0)
#define SM_PASID1_PWSNP         BIT_U64(23)
#define SM_PASID1_PGSNP         BIT_U64(24)
#define SM_PASID1_CD            BIT_U64(25)
#define SM_PASID1_EMTE          BIT_U64(26)
#define SM_PASID1_PAT           GENMASK_U64(63, 32)

#define SM_PASID2_SRE           BIT_U64(0)
#define SM_PASID2_FSPM          GENMASK_U64(3, 2)
#define SM_PASID2_WPE           BIT_U64(4)
#define SM_PASID2_EAFE          BIT_U64(7)
#define SM_PASID2_FSPTPTR       GENMASK_U64(63, 12)

drivers/iommu/intel/pasid.c:

static void intel_pasid_get_used(const u128 *entry, u128 *used)
{
        struct pasid_entry *pe = (struct pasid_entry *)entry;
        struct pasid_entry *ue = (struct pasid_entry *)used;
        u16 pgtt;

        /* Initialize used bits to 0. */
        memset(ue, 0, sizeof(*ue));

        /* Present bit always matters. */
        ue->val[0] |= SM_PASID0_P;

        /* Nothing more for non-present entries. */
        if (!(pe->val[0] & SM_PASID0_P)) {
                trace_entry_get_used(entry, used);
                return;
        }

        pgtt = pasid_pte_get_pgtt(pe);
        switch (pgtt) {
        case PASID_ENTRY_PGTT_FL_ONLY:
                /* AW, PGTT */
                ue->val[0] |= SM_PASID0_AW | SM_PASID0_PGTT;
                /* DID, PWSNP, PGSNP */
                ue->val[1] |= SM_PASID1_DID | SM_PASID1_PWSNP | 
SM_PASID1_PGSNP;
                /* FSPTPTR, FSPM */
                ue->val[2] |= SM_PASID2_FSPTPTR | SM_PASID2_FSPM;
                break;
        case PASID_ENTRY_PGTT_NESTED:
                /* FPD, AW, PGTT, SSADE, SSPTPTR*/
                ue->val[0] |= SM_PASID0_FPD | SM_PASID0_AW | 
SM_PASID0_PGTT |
                                SM_PASID0_SSADE | SM_PASID0_SSPTPTR;
                /* PGSNP, DID, PWSNP */
                ue->val[1] |= SM_PASID1_DID | SM_PASID1_PWSNP | 
SM_PASID1_PGSNP;
                /* FSPTPTR, FSPM, EAFE, WPE, SRE */
                ue->val[2] |= SM_PASID2_SRE | SM_PASID2_WPE | 
SM_PASID2_EAFE |
                                SM_PASID2_FSPM | SM_PASID2_FSPTPTR;
                break;
        case PASID_ENTRY_PGTT_SL_ONLY:
                /* FPD, AW, PGTT, SSADE, SSPTPTR */
                ue->val[0] |= SM_PASID0_FPD | SM_PASID0_AW | 
SM_PASID0_PGTT |
                                SM_PASID0_SSADE | SM_PASID0_SSPTPTR;
                /* PGSNP, DID, PWSNP */
                ue->val[1] |= SM_PASID1_DID | SM_PASID1_PWSNP | 
SM_PASID1_PGSNP;
                break;
        case PASID_ENTRY_PGTT_PT:
                /* FPD, AW, PGTT */
                ue->val[0] |= SM_PASID0_FPD | SM_PASID0_AW | 
SM_PASID0_PGTT;
                /* PGSNP, DID, PWSNP */
                ue->val[1] |= SM_PASID1_DID | SM_PASID1_PWSNP | 
SM_PASID1_PGSNP;
                break;
        default:
                WARN_ON(true);
        }

        trace_entry_get_used(entry, used);
}

Thanks,
baolu