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Message-ID: <CAH2o1u6AEMgMQOGUWYpCVMFQYt0+fNUxSj+dM2S4G7JyYZMJ-A@mail.gmail.com>
Date: Tue, 14 May 2024 11:23:59 -0700
From: Tomasz Jeznach <tjeznach@...osinc.com>
To: Zong Li <zong.li@...ive.com>
Cc: Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>, Paul Walmsley <paul.walmsley@...ive.com>,
Anup Patel <apatel@...tanamicro.com>, devicetree@...r.kernel.org,
Conor Dooley <conor+dt@...nel.org>, Albert Ou <aou@...s.berkeley.edu>, linux@...osinc.com,
linux-kernel@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
Sebastien Boeuf <seb@...osinc.com>, iommu@...ts.linux.dev,
Palmer Dabbelt <palmer@...belt.com>, Nick Kossifidis <mick@....forth.gr>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v4 7/7] iommu/riscv: Paging domain support
On Thu, May 9, 2024 at 12:14 AM Zong Li <zong.li@...ive.com> wrote:
>
> On Thu, May 9, 2024 at 12:13 AM Tomasz Jeznach <tjeznach@...osinccom> wrote:
> >
> > On Wed, May 8, 2024 at 8:57 AM Zong Li <zong.li@...ive.com> wrote:
> > >
> > > On Sat, May 4, 2024 at 12:13 AM Tomasz Jeznach <tjeznach@...osinc.com> wrote:
> > > >
> > > > Introduce first-stage address translation support.
> > > >
> > > > Page table configured by the IOMMU driver will use the highest mode
> > > > implemented by the hardware, unless not known at the domain allocation
> > > > time falling back to the CPU’s MMU page mode.
> > > >
> > > > This change introduces IOTINVAL.VMA command, required to invalidate
> > > > any cached IOATC entries after mapping is updated and/or removed from
> > > > the paging domain. Invalidations for the non-leaf page entries use
> > > > IOTINVAL for all addresses assigned to the protection domain for
> > > > hardware not supporting more granular non-leaf page table cache
> > > > invalidations.
> > > >
> > > > Signed-off-by: Tomasz Jeznach <tjeznach@...osinc.com>
> > > > ---
> > > > drivers/iommu/riscv/iommu.c | 587 +++++++++++++++++++++++++++++++++++-
> > > > 1 file changed, 585 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
> > > > index 4349ac8a3990..ec701fde520f 100644
> > > > --- a/drivers/iommu/riscv/iommu.c
> > > > +++ b/drivers/iommu/riscv/iommu.c
> > > > @@ -41,6 +41,10 @@
> > > > #define dev_to_iommu(dev) \
> > > > iommu_get_iommu_dev(dev, struct riscv_iommu_device, iommu)
> > > >
> > > > +/* IOMMU PSCID allocation namespace. */
> > > > +static DEFINE_IDA(riscv_iommu_pscids);
> > > > +#define RISCV_IOMMU_MAX_PSCID (BIT(20) - 1)
> > > > +
> > > > /* Device resource-managed allocations */
> > > > struct riscv_iommu_devres {
> > > > void *addr;
> > > > @@ -766,6 +770,143 @@ static int riscv_iommu_iodir_set_mode(struct riscv_iommu_device *iommu,
> > > > return 0;
> > > > }
> > > >
> > > > +/* This struct contains protection domain specific IOMMU driver data. */
> > > > +struct riscv_iommu_domain {
> > > > + struct iommu_domain domain;
> > > > + struct list_head bonds;
> > > > + spinlock_t lock; /* protect bonds list updates. */
> > > > + int pscid;
> > > > + int numa_node;
> > > > + int amo_enabled:1;
> > > > + unsigned int pgd_mode;
> > > > + unsigned long *pgd_root;
> > > > +};
> > > > +
> > > > +#define iommu_domain_to_riscv(iommu_domain) \
> > > > + container_of(iommu_domain, struct riscv_iommu_domain, domain)
> > > > +
> > > > +/* Private IOMMU data for managed devices, dev_iommu_priv_* */
> > > > +struct riscv_iommu_info {
> > > > + struct riscv_iommu_domain *domain;
> > > > +};
> > > > +
> > > > +/* Linkage between an iommu_domain and attached devices. */
> > > > +struct riscv_iommu_bond {
> > > > + struct list_head list;
> > > > + struct rcu_head rcu;
> > > > + struct device *dev;
> > > > +};
> > > > +
> > > > +static int riscv_iommu_bond_link(struct riscv_iommu_domain *domain,
> > > > + struct device *dev)
> > > > +{
> > > > + struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> > > > + struct riscv_iommu_bond *bond;
> > > > + struct list_head *bonds;
> > > > +
> > > > + bond = kzalloc(sizeof(*bond), GFP_KERNEL);
> > > > + if (!bond)
> > > > + return -ENOMEM;
> > > > + bond->dev = dev;
> > > > +
> > > > + /*
> > > > + * Linked device pointer and iommu data remain stable in bond struct
> > > > + * as long the device is attached to the managed IOMMU at _probe_device(),
> > > > + * up to completion of _release_device() call. Release of the bond will be
> > > > + * synchronized at the device release, to guarantee no stale pointer is
> > > > + * used inside rcu protected sections.
> > > > + *
> > > > + * List of devices attached to the domain is arranged based on
> > > > + * managed IOMMU device.
> > > > + */
> > > > +
> > > > + spin_lock(&domain->lock);
> > > > + list_for_each_rcu(bonds, &domain->bonds)
> > > > + if (dev_to_iommu(list_entry(bonds, struct riscv_iommu_bond, list)->dev) == iommu)
> > > > + break;
> > > > + list_add_rcu(&bond->list, bonds);
> > > > + spin_unlock(&domain->lock);
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static void riscv_iommu_bond_unlink(struct riscv_iommu_domain *domain,
> > > > + struct device *dev)
> > > > +{
> > > > + struct riscv_iommu_bond *bond, *found = NULL;
> > > > +
> > > > + if (!domain)
> > > > + return;
> > > > +
> > > > + spin_lock(&domain->lock);
> > > > + list_for_each_entry_rcu(bond, &domain->bonds, list) {
> > > > + if (bond->dev == dev) {
> > > > + list_del_rcu(&bond->list);
> > > > + found = bond;
> > > > + }
> > > > + }
> > > > + spin_unlock(&domain->lock);
> > > > + kfree_rcu(found, rcu);
> > > > +}
> > > > +
> > > > +/*
> > > > + * Send IOTLB.INVAL for whole address space for ranges larger than 2MB.
> > > > + * This limit will be replaced with range invalidations, if supported by
> > > > + * the hardware, when RISC-V IOMMU architecture specification update for
> > > > + * range invalidations update will be available.
> > > > + */
> > > > +#define RISCV_IOMMU_IOTLB_INVAL_LIMIT (2 << 20)
> > > > +
> > > > +static void riscv_iommu_iotlb_inval(struct riscv_iommu_domain *domain,
> > > > + unsigned long start, unsigned long end)
> > > > +{
> > > > + struct riscv_iommu_bond *bond;
> > > > + struct riscv_iommu_device *iommu, *prev;
> > > > + struct riscv_iommu_command cmd;
> > > > + unsigned long len = end - start + 1;
> > > > + unsigned long iova;
> > > > +
> > > > + rcu_read_lock();
> > > > +
> > > > + prev = NULL;
> > > > + list_for_each_entry_rcu(bond, &domain->bonds, list) {
> > > > + iommu = dev_to_iommu(bond->dev);
> > > > +
> > > > + /*
> > > > + * IOTLB invalidation request can be safely omitted if already sent
> > > > + * to the IOMMU for the same PSCID, and with domain->bonds list
> > > > + * arranged based on the device's IOMMU, it's sufficient to check
> > > > + * last device the invalidation was sent to.
> > > > + */
> > > > + if (iommu == prev)
> > > > + continue;
> > > > +
> > > > + riscv_iommu_cmd_inval_vma(&cmd);
> > > > + riscv_iommu_cmd_inval_set_pscid(&cmd, domain->pscid);
> > > > + if (len && len >= RISCV_IOMMU_IOTLB_INVAL_LIMIT) {
> > > > + for (iova = start; iova < end; iova += PAGE_SIZE) {
> > > > + riscv_iommu_cmd_inval_set_addr(&cmd, iova);
> > > > + riscv_iommu_cmd_send(iommu, &cmd, 0);
> > > > + }
> > > > + } else {
> > > > + riscv_iommu_cmd_send(iommu, &cmd, 0);
> > > > + }
> > > > + prev = iommu;
> > > > + }
> > > > +
> > > > + prev = NULL;
> > > > + list_for_each_entry_rcu(bond, &domain->bonds, list) {
> > > > + iommu = dev_to_iommu(bond->dev);
> > > > + if (iommu == prev)
> > > > + continue;
> > > > +
> > > > + riscv_iommu_cmd_iofence(&cmd);
> > >
> > > I was wondering why we need many 'iofence' commands following
> > > invalidation commands. Could we just use one iofence to guarantees
> > > that all previous invalidation commands have been completed?
> > >
> >
> > Unless I'm missing something, this code should send only one IOFENCE.C
> > command send per IOMMU device. If there are multiple IOMMU devices
> > involved in the invalidation sequence, we have to wait for all of the
> > invalidation commands to complete, as there is no synchronization
> > mechanism between those independent IOMMUs.
> >
>
> Sorry for confusing, I guess I need to rephrase my question. Is it
> possible that the iommu devices of each device in bonds list are
> interlaced? For instance, iommu device A -> iommu device B -> iommu
> device A -> iommu device B. I was wondering if we need to consider
> this situation and try to ignore second iofence for the repeating
> iommu device, or actually, this situation won't occur.
>
Linked devices (list elements) are arranged based on the referenced
IOMMU. List insertion at riscv_iommu_bond_link() should take care of
it.
> > > > + riscv_iommu_cmd_send(iommu, &cmd, RISCV_IOMMU_QUEUE_TIMEOUT);
> > > > + prev = iommu;
> > > > + }
> > > > + rcu_read_unlock();
> > > > +}
> > > > +
> > > > #define RISCV_IOMMU_FSC_BARE 0
> > > >
> > > > /*
> > > > @@ -785,10 +926,29 @@ static void riscv_iommu_iodir_update(struct riscv_iommu_device *iommu,
> > > > {
> > > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> > > > struct riscv_iommu_dc *dc;
> > > > + struct riscv_iommu_command cmd;
> > > > + bool sync_required = false;
> > > > u64 tc;
> > > > int i;
> > > >
> > > > - /* Device context invalidation ignored for now. */
> > > > + for (i = 0; i < fwspec->num_ids; i++) {
> > > > + dc = riscv_iommu_get_dc(iommu, fwspec->ids[i]);
> > > > + tc = READ_ONCE(dc->tc);
> > > > + if (tc & RISCV_IOMMU_DC_TC_V) {
> > > > + WRITE_ONCE(dc->tc, tc & ~RISCV_IOMMU_DC_TC_V);
> > > > +
> > > > + /* Invalidate device context cached values */
> > > > + riscv_iommu_cmd_iodir_inval_ddt(&cmd);
> > > > + riscv_iommu_cmd_iodir_set_did(&cmd, fwspec->ids[i]);
> > > > + riscv_iommu_cmd_send(iommu, &cmd, 0);
> > > > + sync_required = true;
> > > > + }
> > > > + }
> > > > +
> > > > + if (sync_required) {
> > > > + riscv_iommu_cmd_iofence(&cmd);
> > > > + riscv_iommu_cmd_send(iommu, &cmd, RISCV_IOMMU_IOTINVAL_TIMEOUT);
> > > > + }
> > > >
> > > > /*
> > > > * For device context with DC_TC_PDTV = 0, translation attributes valid bit
> > > > @@ -806,12 +966,415 @@ static void riscv_iommu_iodir_update(struct riscv_iommu_device *iommu,
> > > > }
> > > > }
> > > >
> > > > +/*
> > > > + * IOVA page translation tree management.
> > > > + */
> > > > +
> > > > +#define IOMMU_PAGE_SIZE_4K BIT_ULL(12)
> > > > +#define IOMMU_PAGE_SIZE_2M BIT_ULL(21)
> > > > +#define IOMMU_PAGE_SIZE_1G BIT_ULL(30)
> > > > +#define IOMMU_PAGE_SIZE_512G BIT_ULL(39)
> > > > +
> > > > +#define PT_SHIFT (PAGE_SHIFT - ilog2(sizeof(pte_t)))
> > > > +
> > > > +static void riscv_iommu_iotlb_flush_all(struct iommu_domain *iommu_domain)
> > > > +{
> > > > + struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> > > > +
> > > > + riscv_iommu_iotlb_inval(domain, 0, ULONG_MAX);
> > > > +}
> > > > +
> > > > +static void riscv_iommu_iotlb_sync(struct iommu_domain *iommu_domain,
> > > > + struct iommu_iotlb_gather *gather)
> > > > +{
> > > > + struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> > > > +
> > > > + riscv_iommu_iotlb_inval(domain, gather->start, gather->end);
> > > > +}
> > > > +
> > > > +static inline size_t get_page_size(size_t size)
> > > > +{
> > > > + if (size >= IOMMU_PAGE_SIZE_512G)
> > > > + return IOMMU_PAGE_SIZE_512G;
> > > > + if (size >= IOMMU_PAGE_SIZE_1G)
> > > > + return IOMMU_PAGE_SIZE_1G;
> > > > + if (size >= IOMMU_PAGE_SIZE_2M)
> > > > + return IOMMU_PAGE_SIZE_2M;
> > > > + return IOMMU_PAGE_SIZE_4K;
> > > > +}
> > > > +
> > > > +#define _io_pte_present(pte) ((pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE))
> > > > +#define _io_pte_leaf(pte) ((pte) & _PAGE_LEAF)
> > > > +#define _io_pte_none(pte) ((pte) == 0)
> > > > +#define _io_pte_entry(pn, prot) ((_PAGE_PFN_MASK & ((pn) << _PAGE_PFN_SHIFT)) | (prot))
> > > > +
> > > > +static void riscv_iommu_pte_free(struct riscv_iommu_domain *domain,
> > > > + unsigned long pte, struct list_head *freelist)
> > > > +{
> > > > + unsigned long *ptr;
> > > > + int i;
> > > > +
> > > > + if (!_io_pte_present(pte) || _io_pte_leaf(pte))
> > > > + return;
> > > > +
> > > > + ptr = (unsigned long *)pfn_to_virt(__page_val_to_pfn(pte));
> > > > +
> > > > + /* Recursively free all sub page table pages */
> > > > + for (i = 0; i < PTRS_PER_PTE; i++) {
> > > > + pte = READ_ONCE(ptr[i]);
> > > > + if (!_io_pte_none(pte) && cmpxchg_relaxed(ptr + i, pte, 0) == pte)
> > > > + riscv_iommu_pte_free(domain, pte, freelist);
> > > > + }
> > > > +
> > > > + if (freelist)
> > > > + list_add_tail(&virt_to_page(ptr)->lru, freelist);
> > > > + else
> > > > + iommu_free_page(ptr);
> > > > +}
> > > > +
> > > > +static unsigned long *riscv_iommu_pte_alloc(struct riscv_iommu_domain *domain,
> > > > + unsigned long iova, size_t pgsize,
> > > > + gfp_t gfp)
> > > > +{
> > > > + unsigned long *ptr = domain->pgd_root;
> > > > + unsigned long pte, old;
> > > > + int level = domain->pgd_mode - RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39 + 2;
> > > > + void *addr;
> > > > +
> > > > + do {
> > > > + const int shift = PAGE_SHIFT + PT_SHIFT * level;
> > > > +
> > > > + ptr += ((iova >> shift) & (PTRS_PER_PTE - 1));
> > > > + /*
> > > > + * Note: returned entry might be a non-leaf if there was
> > > > + * existing mapping with smaller granularity. Up to the caller
> > > > + * to replace and invalidate.
> > > > + */
> > > > + if (((size_t)1 << shift) == pgsize)
> > > > + return ptr;
> > > > +pte_retry:
> > > > + pte = READ_ONCE(*ptr);
> > > > + /*
> > > > + * This is very likely incorrect as we should not be adding
> > > > + * new mapping with smaller granularity on top
> > > > + * of existing 2M/1G mapping. Fail.
> > > > + */
> > > > + if (_io_pte_present(pte) && _io_pte_leaf(pte))
> > > > + return NULL;
> > > > + /*
> > > > + * Non-leaf entry is missing, allocate and try to add to the
> > > > + * page table. This might race with other mappings, retry.
> > > > + */
> > > > + if (_io_pte_none(pte)) {
> > > > + addr = iommu_alloc_page_node(domain->numa_node, gfp);
> > > > + if (!addr)
> > > > + return NULL;
> > > > + old = pte;
> > > > + pte = _io_pte_entry(virt_to_pfn(addr), _PAGE_TABLE);
> > > > + if (cmpxchg_relaxed(ptr, old, pte) != old) {
> > > > + iommu_free_page(addr);
> > > > + goto pte_retry;
> > > > + }
> > > > + }
> > > > + ptr = (unsigned long *)pfn_to_virt(__page_val_to_pfn(pte));
> > > > + } while (level-- > 0);
> > > > +
> > > > + return NULL;
> > > > +}
> > > > +
> > > > +static unsigned long *riscv_iommu_pte_fetch(struct riscv_iommu_domain *domain,
> > > > + unsigned long iova, size_t *pte_pgsize)
> > > > +{
> > > > + unsigned long *ptr = domain->pgd_root;
> > > > + unsigned long pte;
> > > > + int level = domain->pgd_mode - RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39 + 2;
> > > > +
> > > > + do {
> > > > + const int shift = PAGE_SHIFT + PT_SHIFT * level;
> > > > +
> > > > + ptr += ((iova >> shift) & (PTRS_PER_PTE - 1));
> > > > + pte = READ_ONCE(*ptr);
> > > > + if (_io_pte_present(pte) && _io_pte_leaf(pte)) {
> > > > + *pte_pgsize = (size_t)1 << shift;
> > > > + return ptr;
> > > > + }
> > > > + if (_io_pte_none(pte))
> > > > + return NULL;
> > > > + ptr = (unsigned long *)pfn_to_virt(__page_val_to_pfn(pte));
> > > > + } while (level-- > 0);
> > > > +
> > > > + return NULL;
> > > > +}
> > > > +
> > > > +static int riscv_iommu_map_pages(struct iommu_domain *iommu_domain,
> > > > + unsigned long iova, phys_addr_t phys,
> > > > + size_t pgsize, size_t pgcount, int prot,
> > > > + gfp_t gfp, size_t *mapped)
> > > > +{
> > > > + struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> > > > + size_t size = 0;
> > > > + size_t page_size = get_page_size(pgsize);
> > > > + unsigned long *ptr;
> > > > + unsigned long pte, old, pte_prot;
> > > > + int rc = 0;
> > > > + LIST_HEAD(freelist);
> > > > +
> > > > + if (!(prot & IOMMU_WRITE))
> > > > + pte_prot = _PAGE_BASE | _PAGE_READ;
> > > > + else if (domain->amo_enabled)
> > > > + pte_prot = _PAGE_BASE | _PAGE_READ | _PAGE_WRITE;
> > > > + else
> > > > + pte_prot = _PAGE_BASE | _PAGE_READ | _PAGE_WRITE | _PAGE_DIRTY;
> > > > +
> > > > + while (pgcount) {
> > > > + ptr = riscv_iommu_pte_alloc(domain, iova, page_size, gfp);
> > > > + if (!ptr) {
> > > > + rc = -ENOMEM;
> > > > + break;
> > > > + }
> > > > +
> > > > + old = READ_ONCE(*ptr);
> > > > + pte = _io_pte_entry(phys_to_pfn(phys), pte_prot);
> > > > + if (cmpxchg_relaxed(ptr, old, pte) != old)
> > > > + continue;
> > > > +
> > > > + riscv_iommu_pte_free(domain, old, &freelist);
> > > > +
> > > > + size += page_size;
> > > > + iova += page_size;
> > > > + phys += page_size;
> > > > + --pgcount;
> > > > + }
> > > > +
> > > > + *mapped = size;
> > > > +
> > > > + if (!list_empty(&freelist)) {
> > > > + /*
> > > > + * In 1.0 spec version, the smallest scope we can use to
> > > > + * invalidate all levels of page table (i.e. leaf and non-leaf)
> > > > + * is an invalidate-all-PSCID IOTINVAL.VMA with AV=0.
> > > > + * This will be updated with hardware support for
> > > > + * capability.NL (non-leaf) IOTINVAL command.
> > > > + */
> > > > + riscv_iommu_iotlb_inval(domain, 0, ULONG_MAX);
> > > > + iommu_put_pages_list(&freelist);
> > > > + }
> > > > +
> > > > + return rc;
> > > > +}
> > > > +
> > > > +static size_t riscv_iommu_unmap_pages(struct iommu_domain *iommu_domain,
> > > > + unsigned long iova, size_t pgsize,
> > > > + size_t pgcount,
> > > > + struct iommu_iotlb_gather *gather)
> > > > +{
> > > > + struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> > > > + size_t size = pgcount << __ffs(pgsize);
> > > > + unsigned long *ptr, old;
> > > > + size_t unmapped = 0;
> > > > + size_t pte_size;
> > > > +
> > > > + while (unmapped < size) {
> > > > + ptr = riscv_iommu_pte_fetch(domain, iova, &pte_size);
> > > > + if (!ptr)
> > > > + return unmapped;
> > > > +
> > > > + /* partial unmap is not allowed, fail. */
> > > > + if (iova & (pte_size - 1))
> > > > + return unmapped;
> > > > +
> > > > + old = READ_ONCE(*ptr);
> > > > + if (cmpxchg_relaxed(ptr, old, 0) != old)
> > > > + continue;
> > > > +
> > > > + iommu_iotlb_gather_add_page(&domain->domain, gather, iova,
> > > > + pte_size);
> > > > +
> > > > + iova += pte_size;
> > > > + unmapped += pte_size;
> > > > + }
> > > > +
> > > > + return unmapped;
> > > > +}
> > > > +
> > > > +static phys_addr_t riscv_iommu_iova_to_phys(struct iommu_domain *iommu_domain,
> > > > + dma_addr_t iova)
> > > > +{
> > > > + struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> > > > + unsigned long pte_size;
> > > > + unsigned long *ptr;
> > > > +
> > > > + ptr = riscv_iommu_pte_fetch(domain, iova, &pte_size);
> > > > + if (_io_pte_none(*ptr) || !_io_pte_present(*ptr))
> > > > + return 0;
> > > > +
> > > > + return pfn_to_phys(__page_val_to_pfn(*ptr)) | (iova & (pte_size - 1));
> > > > +}
> > > > +
> > > > +static void riscv_iommu_free_paging_domain(struct iommu_domain *iommu_domain)
> > > > +{
> > > > + struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> > > > + const unsigned long pfn = virt_to_pfn(domain->pgd_root);
> > > > +
> > > > + WARN_ON(!list_empty(&domain->bonds));
> > > > +
> > > > + if ((int)domain->pscid > 0)
> > > > + ida_free(&riscv_iommu_pscids, domain->pscid);
> > > > +
> > > > + riscv_iommu_pte_free(domain, _io_pte_entry(pfn, _PAGE_TABLE), NULL);
> > > > + kfree(domain);
> > > > +}
> > > > +
> > > > +static bool riscv_iommu_pt_supported(struct riscv_iommu_device *iommu, int pgd_mode)
> > > > +{
> > > > + switch (pgd_mode) {
> > > > + case RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39:
> > > > + return iommu->caps & RISCV_IOMMU_CAP_S_SV39;
> > > > +
> > > > + case RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV48:
> > > > + return iommu->caps & RISCV_IOMMU_CAP_S_SV48;
> > > > +
> > > > + case RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV57:
> > > > + return iommu->caps & RISCV_IOMMU_CAP_S_SV57;
> > > > + }
> > > > + return false;
> > > > +}
> > > > +
> > > > +static int riscv_iommu_attach_paging_domain(struct iommu_domain *iommu_domain,
> > > > + struct device *dev)
> > > > +{
> > > > + struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> > > > + struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> > > > + struct riscv_iommu_info *info = dev_iommu_priv_get(dev);
> > > > + u64 fsc, ta;
> > > > +
> > > > + if (!riscv_iommu_pt_supported(iommu, domain->pgd_mode))
> > > > + return -ENODEV;
> > > > +
> > > > + if (domain->numa_node == NUMA_NO_NODE)
> > > > + domain->numa_node = dev_to_node(iommu->dev);
> > > > +
> > > > + if (riscv_iommu_bond_link(domain, dev))
> > > > + return -ENOMEM;
> > > > +
> > > > + /*
> > > > + * Invalidate PSCID.
> > > > + * This invalidation might be redundant if IOATC has been already cleared,
> > > > + * however we are not keeping track for domains not linked to a device.
> > > > + */
> > > > + riscv_iommu_iotlb_inval(domain, 0, ULONG_MAX);
> > > > +
> > > > + fsc = FIELD_PREP(RISCV_IOMMU_PC_FSC_MODE, domain->pgd_mode) |
> > > > + FIELD_PREP(RISCV_IOMMU_PC_FSC_PPN, virt_to_pfn(domain->pgd_root));
> > > > + ta = FIELD_PREP(RISCV_IOMMU_PC_TA_PSCID, domain->pscid) |
> > > > + RISCV_IOMMU_PC_TA_V;
> > > > +
> > > > + riscv_iommu_iodir_update(iommu, dev, fsc, ta);
> > > > + riscv_iommu_bond_unlink(info->domain, dev);
> > >
> > > Should we unlink bond before link it?
> > >
> >
> > No. This will potentially result in missing mapping invalidation for
> > previously attached (and still valid during
> > riscv_iommu_iodir_update()) domain.
>
> Okay, my original concern was that it would break the list in the old
> domain, but I noticed that it will allocate a new bond instance for
> the new domain. Thanks for clarifying.
>
> >
> > > > + info->domain = domain;
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static const struct iommu_domain_ops riscv_iommu_paging_domain_ops = {
> > > > + .attach_dev = riscv_iommu_attach_paging_domain,
> > > > + .free = riscv_iommu_free_paging_domain,
> > > > + .map_pages = riscv_iommu_map_pages,
> > > > + .unmap_pages = riscv_iommu_unmap_pages,
> > > > + .iova_to_phys = riscv_iommu_iova_to_phys,
> > > > + .iotlb_sync = riscv_iommu_iotlb_sync,
> > > > + .flush_iotlb_all = riscv_iommu_iotlb_flush_all,
> > > > +};
> > > > +
> > > > +static struct iommu_domain *riscv_iommu_alloc_paging_domain(struct device *dev)
> > > > +{
> > > > + struct riscv_iommu_domain *domain;
> > > > + struct riscv_iommu_device *iommu;
> > > > + unsigned int pgd_mode;
> > > > + int va_bits;
> > > > +
> > > > + iommu = dev ? dev_to_iommu(dev) : NULL;
> > > > +
> > > > + /*
> > > > + * In unlikely case when dev or iommu is not known, use system
> > > > + * SATP mode to configure paging domain radix tree depth.
> > > > + * Use highest available if actual IOMMU hardware capabilities
> > > > + * are known here.
> > > > + */
> > > > + if (!iommu) {
> > > > + pgd_mode = satp_mode >> SATP_MODE_SHIFT;
> > > > + va_bits = VA_BITS;
> > > > + } else if (iommu->caps & RISCV_IOMMU_CAP_S_SV57) {
> > > > + pgd_mode = RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV57;
> > > > + va_bits = 57;
> > > > + } else if (iommu->caps & RISCV_IOMMU_CAP_S_SV48) {
> > > > + pgd_mode = RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV48;
> > > > + va_bits = 48;
> > > > + } else if (iommu->caps & RISCV_IOMMU_CAP_S_SV39) {
> > > > + pgd_mode = RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39;
> > > > + va_bits = 39;
> > > > + } else {
> > > > + dev_err(dev, "cannot find supported page table mode\n");
> > > > + return ERR_PTR(-ENODEV);
> > > > + }
> > > > +
> > > > + domain = kzalloc(sizeof(*domain), GFP_KERNEL);
> > > > + if (!domain)
> > > > + return ERR_PTR(-ENOMEM);
> > > > +
> > > > + INIT_LIST_HEAD_RCU(&domain->bonds);
> > > > + spin_lock_init(&domain->lock);
> > > > + domain->numa_node = NUMA_NO_NODE;
> > > > +
> > > > + if (iommu) {
> > > > + domain->numa_node = dev_to_node(iommu->dev);
> > > > + domain->amo_enabled = !!(iommu->caps & RISCV_IOMMU_CAP_AMO_HWAD);
> > > > + }
> > > > +
> > > > + domain->pgd_mode = pgd_mode;
> > > > + domain->pgd_root = iommu_alloc_page_node(domain->numa_node,
> > > > + GFP_KERNEL_ACCOUNT);
> > > > + if (!domain->pgd_root) {
> > > > + kfree(domain);
> > > > + return ERR_PTR(-ENOMEM);
> > > > + }
> > > > +
> > > > + domain->pscid = ida_alloc_range(&riscv_iommu_pscids, 1,
> > > > + RISCV_IOMMU_MAX_PSCID, GFP_KERNEL);
> > > > + if (domain->pscid < 0) {
> > > > + iommu_free_page(domain->pgd_root);
> > > > + kfree(domain);
> > > > + return ERR_PTR(-ENOMEM);
> > > > + }
> > > > +
> > > > + /*
> > > > + * Note: RISC-V Privilege spec mandates that virtual addresses
> > > > + * need to be sign-extended, so if (VA_BITS - 1) is set, all
> > > > + * bits >= VA_BITS need to also be set or else we'll get a
> > > > + * page fault. However the code that creates the mappings
> > > > + * above us (e.g. iommu_dma_alloc_iova()) won't do that for us
> > > > + * for now, so we'll end up with invalid virtual addresses
> > > > + * to map. As a workaround until we get this sorted out
> > > > + * limit the available virtual addresses to VA_BITS - 1.
> > > > + */
> > > > + domain->domain.geometry.aperture_start = 0;
> > > > + domain->domain.geometry.aperture_end = DMA_BIT_MASK(va_bits - 1);
> > > > + domain->domain.geometry.force_aperture = true;
> > > > +
> > > > + domain->domain.ops = &riscv_iommu_paging_domain_ops;
> > > > +
> > > > + return &domain->domain;
> > > > +}
> > > > +
> > > > static int riscv_iommu_attach_blocking_domain(struct iommu_domain *iommu_domain,
> > > > struct device *dev)
> > > > {
> > > > struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> > > > + struct riscv_iommu_info *info = dev_iommu_priv_get(dev);
> > > >
> > > > riscv_iommu_iodir_update(iommu, dev, RISCV_IOMMU_FSC_BARE, 0);
> > > > + riscv_iommu_bond_unlink(info->domain, dev);
> > > > + info->domain = NULL;
> > > >
> > > > return 0;
> > > > }
> > > > @@ -827,8 +1390,11 @@ static int riscv_iommu_attach_identity_domain(struct iommu_domain *iommu_domain,
> > > > struct device *dev)
> > > > {
> > > > struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> > > > + struct riscv_iommu_info *info = dev_iommu_priv_get(dev);
> > > >
> > > > riscv_iommu_iodir_update(iommu, dev, RISCV_IOMMU_FSC_BARE, RISCV_IOMMU_PC_TA_V);
> > > > + riscv_iommu_bond_unlink(info->domain, dev);
> > > > + info->domain = NULL;
> > > >
> > > > return 0;
> > > > }
> > > > @@ -842,7 +1408,7 @@ static struct iommu_domain riscv_iommu_identity_domain = {
> > > >
> > > > static int riscv_iommu_device_domain_type(struct device *dev)
> > > > {
> > > > - return IOMMU_DOMAIN_IDENTITY;
> > > > + return 0;
> > > > }
> > > >
> > > > static struct iommu_group *riscv_iommu_device_group(struct device *dev)
> > > > @@ -861,6 +1427,7 @@ static struct iommu_device *riscv_iommu_probe_device(struct device *dev)
> > > > {
> > > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> > > > struct riscv_iommu_device *iommu;
> > > > + struct riscv_iommu_info *info;
> > > > struct riscv_iommu_dc *dc;
> > > > u64 tc;
> > > > int i;
> > > > @@ -895,17 +1462,33 @@ static struct iommu_device *riscv_iommu_probe_device(struct device *dev)
> > > > WRITE_ONCE(dc->tc, tc);
> > > > }
> > > >
> > > > + info = kzalloc(sizeof(*info), GFP_KERNEL);
> > > > + if (!info)
> > > > + return ERR_PTR(-ENOMEM);
> > > > + dev_iommu_priv_set(dev, info);
> > > > +
> > > > return &iommu->iommu;
> > > > }
> > > >
> > > > +static void riscv_iommu_release_device(struct device *dev)
> > > > +{
> > > > + struct riscv_iommu_info *info = dev_iommu_priv_get(dev);
> > > > +
> > > > + synchronize_rcu();
> > > > + kfree(info);
> > > > +}
> > > > +
> > > > static const struct iommu_ops riscv_iommu_ops = {
> > > > + .pgsize_bitmap = SZ_4K,
> > > > .of_xlate = riscv_iommu_of_xlate,
> > > > .identity_domain = &riscv_iommu_identity_domain,
> > > > .blocked_domain = &riscv_iommu_blocking_domain,
> > > > .release_domain = &riscv_iommu_blocking_domain,
> > > > + .domain_alloc_paging = riscv_iommu_alloc_paging_domain,
> > > > .def_domain_type = riscv_iommu_device_domain_type,
> > > > .device_group = riscv_iommu_device_group,
> > > > .probe_device = riscv_iommu_probe_device,
> > > > + .release_device = riscv_iommu_release_device,
> > > > };
> > > >
> > > > static int riscv_iommu_init_check(struct riscv_iommu_device *iommu)
> > > > --
> > > > 2.34.1
> > > >
> >
> > Best regards,
> > - Tomasz
> >
> >
Best,
- Tomasz
> > > >
> > > > _______________________________________________
> > > > linux-riscv mailing list
> > > > linux-riscv@...ts.infradead.org
> > > > http://lists.infradead.org/mailman/listinfo/linux-riscv
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