Re: [PATCH v2 3/4] iommu/dma-iommu: Use the dev->coherent_dma_mask
On Mon, May 06, 2019 at 06:56:13PM +0100, Tom Murphy wrote: > Just to make this clear, I won't apply Christoph's patch (the one in > this email thread) and instead the only change I will make is to > rename dma_limit to dma_mask. Sounds good for now. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH v2 3/4] iommu/dma-iommu: Use the dev->coherent_dma_mask
Just to make this clear, I won't apply Christoph's patch (the one in this email thread) and instead the only change I will make is to rename dma_limit to dma_mask. On Tue, Apr 30, 2019 at 1:05 PM Robin Murphy wrote: > > On 30/04/2019 12:32, Christoph Hellwig wrote: > > On Tue, Apr 30, 2019 at 12:27:02PM +0100, Robin Murphy wrote: > >>> Hmm, I don't think we need the DMA mask for the MSI mapping, this > >>> should probably always use a 64-bit mask. > >> > >> If that were true then we wouldn't need DMA masks for regular mappings > >> either. If we have to map the MSI doorbell at all, then we certainly have > >> to > >> place it at an IOVA that the relevant device is actually capable of > >> addressing. > > > > Well, as shown by the patch below we don't even look at the DMA mask > > for the MSI page - we just allocate from bottom to top. > > In the trivial cookie for unmanaged domains, yes, but in that case the > responsibility is on VFIO to provide a suitable (i.e. sub-32-bit) > address range for that cookie in the first place. In the managed case, > allocation uses the streaming mask via iommu_dma_get_msi_page() calling > __iommu_dma_map(). Admittedly the mask can then get overlooked when > reusing an existing mapping, which strictly could pose a problem if you > have multiple devices with incompatible masks in the same group (and > such that the PCI stuff doesn't already mitigate it), but that's such an > obscure corner case that I'm reticent to introduce the complication to > handle it until it's actually proven necessary. > > Robin. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH v2 3/4] iommu/dma-iommu: Use the dev->coherent_dma_mask
On 30/04/2019 12:32, Christoph Hellwig wrote: On Tue, Apr 30, 2019 at 12:27:02PM +0100, Robin Murphy wrote: Hmm, I don't think we need the DMA mask for the MSI mapping, this should probably always use a 64-bit mask. If that were true then we wouldn't need DMA masks for regular mappings either. If we have to map the MSI doorbell at all, then we certainly have to place it at an IOVA that the relevant device is actually capable of addressing. Well, as shown by the patch below we don't even look at the DMA mask for the MSI page - we just allocate from bottom to top. In the trivial cookie for unmanaged domains, yes, but in that case the responsibility is on VFIO to provide a suitable (i.e. sub-32-bit) address range for that cookie in the first place. In the managed case, allocation uses the streaming mask via iommu_dma_get_msi_page() calling __iommu_dma_map(). Admittedly the mask can then get overlooked when reusing an existing mapping, which strictly could pose a problem if you have multiple devices with incompatible masks in the same group (and such that the PCI stuff doesn't already mitigate it), but that's such an obscure corner case that I'm reticent to introduce the complication to handle it until it's actually proven necessary. Robin. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH v2 3/4] iommu/dma-iommu: Use the dev->coherent_dma_mask
On Tue, Apr 30, 2019 at 12:27:02PM +0100, Robin Murphy wrote: > > Hmm, I don't think we need the DMA mask for the MSI mapping, this > > should probably always use a 64-bit mask. > > If that were true then we wouldn't need DMA masks for regular mappings > either. If we have to map the MSI doorbell at all, then we certainly have to > place it at an IOVA that the relevant device is actually capable of > addressing. Well, as shown by the patch below we don't even look at the DMA mask for the MSI page - we just allocate from bottom to top. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH v2 3/4] iommu/dma-iommu: Use the dev->coherent_dma_mask
On 30/04/2019 12:12, Christoph Hellwig wrote:
static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
- size_t size, int prot, struct iommu_domain *domain)
+ size_t size, int prot, struct iommu_domain *domain,
+ dma_addr_t dma_limit)
Can we just call this dma_mask?
static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
@@ -1250,7 +1251,8 @@ static struct iommu_dma_msi_page
*iommu_dma_get_msi_page(struct device *dev,
if (!msi_page)
return NULL;
- iova = __iommu_dma_map(dev, msi_addr, size, prot, domain);
+ iova = __iommu_dma_map(dev, msi_addr, size, prot, domain,
+ dma_get_mask(dev));
Hmm, I don't think we need the DMA mask for the MSI mapping, this
should probably always use a 64-bit mask.
If that were true then we wouldn't need DMA masks for regular mappings
either. If we have to map the MSI doorbell at all, then we certainly
have to place it at an IOVA that the relevant device is actually capable
of addressing.
Robin.
Or we could just untangle
it from the DMA mapping fast path entire, something like:
---
From 0debafc85174ca830f2e371ff8e8f7465bde3ad8 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig
Date: Tue, 30 Apr 2019 07:06:23 -0400
Subject: iommu/dma: opencode __iommu_dma_map in iommu_dma_get_msi_page
The MSI page mapping really is a little different from the normal DMA
mappings and doesn't need to look at the DMA mask. Just open code
it instead of trying to squeeze the behavior into the DMA path helpers.
Signed-off-by: Christoph Hellwig
---
drivers/iommu/dma-iommu.c | 27 +++
1 file changed, 7 insertions(+), 20 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 58c35bab7626..2ac0df0879d7 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -358,11 +358,6 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain
*domain,
struct iova_domain *iovad = >iovad;
unsigned long shift, iova_len, iova = 0;
- if (cookie->type == IOMMU_DMA_MSI_COOKIE) {
- cookie->msi_iova += size;
- return cookie->msi_iova - size;
- }
-
shift = iova_shift(iovad);
iova_len = size >> shift;
/*
@@ -397,10 +392,7 @@ static void iommu_dma_free_iova(struct iommu_dma_cookie
*cookie,
{
struct iova_domain *iovad = >iovad;
- /* The MSI case is only ever cleaning up its most recent allocation */
- if (cookie->type == IOMMU_DMA_MSI_COOKIE)
- cookie->msi_iova -= size;
- else if (cookie->fq_domain) /* non-strict mode */
+ if (cookie->fq_domain) /* non-strict mode */
queue_iova(iovad, iova_pfn(iovad, iova),
size >> iova_shift(iovad), 0);
else
@@ -430,14 +422,10 @@ static dma_addr_t __iommu_dma_map(struct device *dev,
phys_addr_t phys,
{
struct iommu_domain *domain = iommu_get_dma_domain(dev);
struct iommu_dma_cookie *cookie = domain->iova_cookie;
- size_t iova_off = 0;
+ size_t iova_off = iova_offset(>iovad, phys);
dma_addr_t iova;
- if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
- iova_off = iova_offset(>iovad, phys);
- size = iova_align(>iovad, size + iova_off);
- }
-
+ size = iova_align(>iovad, size + iova_off);
iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
if (!iova)
return DMA_MAPPING_ERROR;
@@ -1121,7 +1109,6 @@ static struct iommu_dma_msi_page
*iommu_dma_get_msi_page(struct device *dev,
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iommu_dma_msi_page *msi_page;
- dma_addr_t iova;
int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
size_t size = cookie_msi_granule(cookie);
@@ -1134,16 +1121,16 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
if (!msi_page)
return NULL;
- iova = __iommu_dma_map(dev, msi_addr, size, prot);
- if (iova == DMA_MAPPING_ERROR)
+ if (iommu_map(domain, cookie->msi_iova, msi_addr, size, prot))
goto out_free_page;
INIT_LIST_HEAD(_page->list);
msi_page->phys = msi_addr;
- msi_page->iova = iova;
+ msi_page->iova = cookie->msi_iova;
list_add(_page->list, >msi_page_list);
- return msi_page;
+ cookie->msi_iova += size;
+ return msi_page;
out_free_page:
kfree(msi_page);
return NULL;
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Re: [PATCH v2 3/4] iommu/dma-iommu: Use the dev->coherent_dma_mask
> static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
> - size_t size, int prot, struct iommu_domain *domain)
> + size_t size, int prot, struct iommu_domain *domain,
> + dma_addr_t dma_limit)
Can we just call this dma_mask?
> static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
> @@ -1250,7 +1251,8 @@ static struct iommu_dma_msi_page
> *iommu_dma_get_msi_page(struct device *dev,
> if (!msi_page)
> return NULL;
>
> - iova = __iommu_dma_map(dev, msi_addr, size, prot, domain);
> + iova = __iommu_dma_map(dev, msi_addr, size, prot, domain,
> + dma_get_mask(dev));
Hmm, I don't think we need the DMA mask for the MSI mapping, this
should probably always use a 64-bit mask. Or we could just untangle
it from the DMA mapping fast path entire, something like:
---
>From 0debafc85174ca830f2e371ff8e8f7465bde3ad8 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig
Date: Tue, 30 Apr 2019 07:06:23 -0400
Subject: iommu/dma: opencode __iommu_dma_map in iommu_dma_get_msi_page
The MSI page mapping really is a little different from the normal DMA
mappings and doesn't need to look at the DMA mask. Just open code
it instead of trying to squeeze the behavior into the DMA path helpers.
Signed-off-by: Christoph Hellwig
---
drivers/iommu/dma-iommu.c | 27 +++
1 file changed, 7 insertions(+), 20 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 58c35bab7626..2ac0df0879d7 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -358,11 +358,6 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain
*domain,
struct iova_domain *iovad = >iovad;
unsigned long shift, iova_len, iova = 0;
- if (cookie->type == IOMMU_DMA_MSI_COOKIE) {
- cookie->msi_iova += size;
- return cookie->msi_iova - size;
- }
-
shift = iova_shift(iovad);
iova_len = size >> shift;
/*
@@ -397,10 +392,7 @@ static void iommu_dma_free_iova(struct iommu_dma_cookie
*cookie,
{
struct iova_domain *iovad = >iovad;
- /* The MSI case is only ever cleaning up its most recent allocation */
- if (cookie->type == IOMMU_DMA_MSI_COOKIE)
- cookie->msi_iova -= size;
- else if (cookie->fq_domain) /* non-strict mode */
+ if (cookie->fq_domain) /* non-strict mode */
queue_iova(iovad, iova_pfn(iovad, iova),
size >> iova_shift(iovad), 0);
else
@@ -430,14 +422,10 @@ static dma_addr_t __iommu_dma_map(struct device *dev,
phys_addr_t phys,
{
struct iommu_domain *domain = iommu_get_dma_domain(dev);
struct iommu_dma_cookie *cookie = domain->iova_cookie;
- size_t iova_off = 0;
+ size_t iova_off = iova_offset(>iovad, phys);
dma_addr_t iova;
- if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
- iova_off = iova_offset(>iovad, phys);
- size = iova_align(>iovad, size + iova_off);
- }
-
+ size = iova_align(>iovad, size + iova_off);
iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
if (!iova)
return DMA_MAPPING_ERROR;
@@ -1121,7 +1109,6 @@ static struct iommu_dma_msi_page
*iommu_dma_get_msi_page(struct device *dev,
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iommu_dma_msi_page *msi_page;
- dma_addr_t iova;
int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
size_t size = cookie_msi_granule(cookie);
@@ -1134,16 +1121,16 @@ static struct iommu_dma_msi_page
*iommu_dma_get_msi_page(struct device *dev,
if (!msi_page)
return NULL;
- iova = __iommu_dma_map(dev, msi_addr, size, prot);
- if (iova == DMA_MAPPING_ERROR)
+ if (iommu_map(domain, cookie->msi_iova, msi_addr, size, prot))
goto out_free_page;
INIT_LIST_HEAD(_page->list);
msi_page->phys = msi_addr;
- msi_page->iova = iova;
+ msi_page->iova = cookie->msi_iova;
list_add(_page->list, >msi_page_list);
- return msi_page;
+ cookie->msi_iova += size;
+ return msi_page;
out_free_page:
kfree(msi_page);
return NULL;
--
2.20.1
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