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Message-ID: <20111014133510.GC2198@amd.com>
Date: Fri, 14 Oct 2011 15:35:10 +0200
From: "Roedel, Joerg" <Joerg.Roedel@....com>
To: Ohad Ben-Cohen <ohad@...ery.com>
CC: "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
David Woodhouse <dwmw2@...radead.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
David Brown <davidb@...eaurora.org>,
Arnd Bergmann <arnd@...db.de>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Stepan Moskovchenko <stepanm@...eaurora.org>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
Hiroshi Doyu <hdoyu@...dia.com>
Subject: Re: [PATCH v3 1/6] iommu/core: split mapping to page sizes as
supported by the hardware
On Tue, Oct 11, 2011 at 01:01:23PM -0400, Ohad Ben-Cohen wrote:
> On Tue, Oct 11, 2011 at 12:38 PM, Roedel, Joerg <Joerg.Roedel@....com> wrote:
> > You need to make sure that you don;t pass larger regions then requested
> > to the low-level driver. Some logic like in the iommu_map function
> > should do it.
>
> You're right. But the solution IMHO should be getting rid of that size
> -> order -> size conversion which we do back and forth, as it's kinda
> pointless.
Right.
>
> > Please use PAGE_SIZE instead of 0x1000UL.
>
> This one would go away too if we remove the size -> order -> size
> conversions. In fact, iommu_unmap() just becomes so much simpler when
> we do that.
>
> I'm attaching two patches: first one that removes the
> size->order->size conversions we have, and then the usual pgsize patch
> rebased to it.
>
> Please take a look,
>
> Thanks,
> Ohad.
>
> >From 7102bda53a425872591f14f850ab031b1ca5dae1 Mon Sep 17 00:00:00 2001
> From: Ohad Ben-Cohen <ohad@...ery.com>
> Date: Tue, 11 Oct 2011 16:50:38 +0200
> Subject: [PATCH 1/2] iommu/core: stop converting bytes to page order
> back and forth
>
> Express sizes in bytes rather than in page order, to eliminate the
> size->order->size conversions we have whenever the IOMMU API is calling
> the low level drivers' map/unmap methods.
>
> Adopt all existing drivers.
>
> Signed-off-by: Ohad Ben-Cohen <ohad@...ery.com>
> ---
> drivers/iommu/amd_iommu.c | 13 +++++--------
> drivers/iommu/intel-iommu.c | 11 ++++-------
> drivers/iommu/iommu.c | 8 +++++---
> drivers/iommu/msm_iommu.c | 19 +++++++------------
> drivers/iommu/omap-iommu.c | 14 +++++---------
> include/linux/iommu.h | 6 +++---
> 6 files changed, 29 insertions(+), 42 deletions(-)
This patch looks good. Please include it in the page-size patch-set.
> drivers/iommu/iommu.c | 112 +++++++++++++++++++++++++++++++++++++++----
> drivers/iommu/omap-iovmm.c | 17 ++----
> include/linux/iommu.h | 24 ++++++++-
> virt/kvm/iommu.c | 8 ++--
> 4 files changed, 132 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 5d042e8..9355632 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -16,6 +16,8 @@
> * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> */
>
> +#define pr_fmt(fmt) "%s: " fmt, __func__
> +
> #include <linux/device.h>
> #include <linux/kernel.h>
> #include <linux/bug.h>
> @@ -47,6 +49,19 @@ int bus_set_iommu(struct bus_type *bus, struct
> iommu_ops *ops)
> if (bus->iommu_ops != NULL)
> return -EBUSY;
>
> + /*
> + * Set the default pgsize values, which retain the existing
> + * IOMMU API behavior: drivers will be called to map
> + * regions that are sized/aligned to order of 4KiB pages.
> + *
> + * This will be removed once all drivers are migrated.
> + */
> + if (!ops->pgsize_bitmap)
> + ops->pgsize_bitmap = ~0xFFFUL;
> +
> + /* find out the minimum page size only once */
> + ops->min_pagesz = 1 << __ffs(ops->pgsize_bitmap);
Hmm, I'd like to constify the iommu_ops structures in the future. This
wouldn't work then anymore. How about renaming it to io_page_size
(because it is the base page-size of the iommu) and let the driver set
it?
> +
> bus->iommu_ops = ops;
>
> /* Do IOMMU specific setup for this bus-type */
> @@ -157,35 +172,110 @@ int iommu_domain_has_cap(struct iommu_domain *domain,
> EXPORT_SYMBOL_GPL(iommu_domain_has_cap);
>
> int iommu_map(struct iommu_domain *domain, unsigned long iova,
> - phys_addr_t paddr, int gfp_order, int prot)
> + phys_addr_t paddr, size_t size, int prot)
> {
> - size_t size;
> + unsigned long orig_iova = iova;
> + size_t orig_size = size;
> + int ret = 0;
>
> if (unlikely(domain->ops->map == NULL))
> return -ENODEV;
>
> - size = PAGE_SIZE << gfp_order;
> + /*
> + * both the virtual address and the physical one, as well as
> + * the size of the mapping, must be aligned (at least) to the
> + * size of the smallest page supported by the hardware
> + */
> + if (!IS_ALIGNED(iova | paddr | size, domain->ops->min_pagesz)) {
> + pr_err("unaligned: iova 0x%lx pa 0x%lx size 0x%x min_pagesz "
> + "0x%x\n", iova, (unsigned long)paddr,
> + size, domain->ops->min_pagesz);
> + return -EINVAL;
> + }
> +
> + pr_debug("map: iova 0x%lx pa 0x%lx size 0x%x\n", iova,
> + (unsigned long)paddr, size);
> +
> + while (size) {
> + unsigned long pgsize, addr_merge = iova | paddr;
> + unsigned int pgsize_idx;
> +
> + /* Max page size that still fits into 'size' */
> + pgsize_idx = __fls(size);
> +
> + /* need to consider alignment requirements ? */
> + if (likely(addr_merge)) {
> + /* Max page size allowed by both iova and paddr */
> + unsigned int align_pgsize_idx = __ffs(addr_merge);
> +
> + pgsize_idx = min(pgsize_idx, align_pgsize_idx);
> + }
> +
> + /* build a mask of acceptable page sizes */
> + pgsize = (1UL << (pgsize_idx + 1)) - 1;
>
> - BUG_ON(!IS_ALIGNED(iova | paddr, size));
> + /* throw away page sizes not supported by the hardware */
> + pgsize &= domain->ops->pgsize_bitmap;
>
> - return domain->ops->map(domain, iova, paddr, size, prot);
> + /* make sure we're still sane */
> + BUG_ON(!pgsize);
> +
> + /* pick the biggest page */
> + pgsize_idx = __fls(pgsize);
> + pgsize = 1UL << pgsize_idx;
> +
> + pr_debug("mapping: iova 0x%lx pa 0x%lx pgsize %lu\n", iova,
> + (unsigned long)paddr, pgsize);
> +
> + ret = domain->ops->map(domain, iova, paddr, pgsize, prot);
> + if (ret)
> + break;
> +
> + iova += pgsize;
> + paddr += pgsize;
> + size -= pgsize;
> + }
> +
> + /* unroll mapping in case something went wrong */
> + if (ret)
> + iommu_unmap(domain, orig_iova, orig_size - size);
> +
> + return ret;
> }
> EXPORT_SYMBOL_GPL(iommu_map);
>
> -int iommu_unmap(struct iommu_domain *domain, unsigned long iova, int gfp_order)
> +size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
> size_t size)
> {
> - size_t size, unmapped;
> + size_t unmapped, left = size;
>
> if (unlikely(domain->ops->unmap == NULL))
> return -ENODEV;
>
> - size = PAGE_SIZE << gfp_order;
> + /*
> + * The virtual address, as well as the size of the mapping, must be
> + * aligned (at least) to the size of the smallest page supported
> + * by the hardware
> + */
> + if (!IS_ALIGNED(iova | size, domain->ops->min_pagesz)) {
> + pr_err("unaligned: iova 0x%lx size 0x%x min_pagesz 0x%x\n",
> + iova, size, domain->ops->min_pagesz);
> + return -EINVAL;
> + }
> +
> + pr_debug("unmap this: iova 0x%lx size 0x%x\n", iova, size);
> +
> + while (left) {
This needs to be (left > 0). The drivers are allowed to unmap more then
requested, so this value may turn negative.
> + unmapped = domain->ops->unmap(domain, iova, left);
> + if (!unmapped)
> + break;
>
> - BUG_ON(!IS_ALIGNED(iova, size));
> + pr_debug("unmapped: iova 0x%lx size %u\n", iova, unmapped);
>
> - unmapped = domain->ops->unmap(domain, iova, size);
> + iova += unmapped;
> + left -= unmapped;
> + }
>
> - return get_order(unmapped);
> + return size - left;
> }
> EXPORT_SYMBOL_GPL(iommu_unmap);
>
> diff --git a/drivers/iommu/omap-iovmm.c b/drivers/iommu/omap-iovmm.c
> index e8fdb88..0b7b14c 100644
> --- a/drivers/iommu/omap-iovmm.c
> +++ b/drivers/iommu/omap-iovmm.c
> @@ -409,7 +409,6 @@ static int map_iovm_area(struct iommu_domain
> *domain, struct iovm_struct *new,
> unsigned int i, j;
> struct scatterlist *sg;
> u32 da = new->da_start;
> - int order;
>
> if (!domain || !sgt)
> return -EINVAL;
> @@ -428,12 +427,10 @@ static int map_iovm_area(struct iommu_domain
> *domain, struct iovm_struct *new,
> if (bytes_to_iopgsz(bytes) < 0)
> goto err_out;
>
> - order = get_order(bytes);
> -
> pr_debug("%s: [%d] %08x %08x(%x)\n", __func__,
> i, da, pa, bytes);
>
> - err = iommu_map(domain, da, pa, order, flags);
> + err = iommu_map(domain, da, pa, bytes, flags);
> if (err)
> goto err_out;
>
> @@ -448,10 +445,9 @@ err_out:
> size_t bytes;
>
> bytes = sg->length + sg->offset;
> - order = get_order(bytes);
>
> /* ignore failures.. we're already handling one */
> - iommu_unmap(domain, da, order);
> + iommu_unmap(domain, da, bytes);
>
> da += bytes;
> }
> @@ -466,7 +462,8 @@ static void unmap_iovm_area(struct iommu_domain
> *domain, struct omap_iommu *obj,
> size_t total = area->da_end - area->da_start;
> const struct sg_table *sgt = area->sgt;
> struct scatterlist *sg;
> - int i, err;
> + int i;
> + size_t unmapped;
>
> BUG_ON(!sgtable_ok(sgt));
> BUG_ON((!total) || !IS_ALIGNED(total, PAGE_SIZE));
> @@ -474,13 +471,11 @@ static void unmap_iovm_area(struct iommu_domain
> *domain, struct omap_iommu *obj,
> start = area->da_start;
> for_each_sg(sgt->sgl, sg, sgt->nents, i) {
> size_t bytes;
> - int order;
>
> bytes = sg->length + sg->offset;
> - order = get_order(bytes);
>
> - err = iommu_unmap(domain, start, order);
> - if (err < 0)
> + unmapped = iommu_unmap(domain, start, bytes);
> + if (unmapped < bytes)
> break;
>
> dev_dbg(obj->dev, "%s: unmap %08x(%x) %08x\n",
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 6b6ed21..76d7ce4 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -48,6 +48,22 @@ struct iommu_domain {
>
> #ifdef CONFIG_IOMMU_API
>
> +/**
> + * struct iommu_ops - iommu ops and capabilities
> + * @domain_init: init iommu domain
> + * @domain_destroy: destroy iommu domain
> + * @attach_dev: attach device to an iommu domain
> + * @detach_dev: detach device from an iommu domain
> + * @map: map a physically contiguous memory region to an iommu domain
> + * @unmap: unmap a physically contiguous memory region from an iommu domain
> + * @iova_to_phys: translate iova to physical address
> + * @domain_has_cap: domain capabilities query
> + * @commit: commit iommu domain
> + * @pgsize_bitmap: bitmap of supported page sizes
> + * @min_pagesz: smallest page size supported. note: this member is private
> + * to the IOMMU core, and maintained only for efficiency sake;
> + * drivers don't need to set it.
> + */
> struct iommu_ops {
> int (*domain_init)(struct iommu_domain *domain);
> void (*domain_destroy)(struct iommu_domain *domain);
> @@ -62,6 +78,8 @@ struct iommu_ops {
> int (*domain_has_cap)(struct iommu_domain *domain,
> unsigned long cap);
> void (*commit)(struct iommu_domain *domain);
> + unsigned long pgsize_bitmap;
> + unsigned int min_pagesz;
> };
>
> extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
> @@ -73,9 +91,9 @@ extern int iommu_attach_device(struct iommu_domain *domain,
> extern void iommu_detach_device(struct iommu_domain *domain,
> struct device *dev);
> extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
> - phys_addr_t paddr, int gfp_order, int prot);
> -extern int iommu_unmap(struct iommu_domain *domain, unsigned long iova,
> - int gfp_order);
> + phys_addr_t paddr, size_t size, int prot);
> +extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
> + size_t size);
> extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
> unsigned long iova);
> extern int iommu_domain_has_cap(struct iommu_domain *domain,
> diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
> index ca409be..35ed096 100644
> --- a/virt/kvm/iommu.c
> +++ b/virt/kvm/iommu.c
> @@ -111,7 +111,7 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct
> kvm_memory_slot *slot)
>
> /* Map into IO address space */
> r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
> - get_order(page_size), flags);
> + page_size, flags);
> if (r) {
> printk(KERN_ERR "kvm_iommu_map_address:"
> "iommu failed to map pfn=%llx\n", pfn);
> @@ -292,15 +292,15 @@ static void kvm_iommu_put_pages(struct kvm *kvm,
>
> while (gfn < end_gfn) {
> unsigned long unmap_pages;
> - int order;
> + size_t size;
>
> /* Get physical address */
> phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
> pfn = phys >> PAGE_SHIFT;
>
> /* Unmap address from IO address space */
> - order = iommu_unmap(domain, gfn_to_gpa(gfn), 0);
> - unmap_pages = 1ULL << order;
> + size = iommu_unmap(domain, gfn_to_gpa(gfn), PAGE_SIZE);
> + unmap_pages = 1ULL << get_order(size);
>
> /* Unpin all pages we just unmapped to not leak any memory */
> kvm_unpin_pages(kvm, pfn, unmap_pages);
> --
> 1.7.4.1
Btw, how have you tested this code?
Regards,
Joerg
--
AMD Operating System Research Center
Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632
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