drivers/xen/swiotlb-xen.c | 7 +------ include/linux/dma-map-ops.h | 2 ++ kernel/dma/ops_helpers.c | 16 ++++++++++++++-- 3 files changed, 17 insertions(+), 8 deletions(-)
From: Roman Skakun <Roman_Skakun@epam.com>
This commit is dedicated to fix incorrect conversion from
cpu_addr to page address in cases when we get virtual
address which allocated in the vmalloc range.
As the result, virt_to_page() cannot convert this address
properly and return incorrect page address.
Need to detect such cases and obtains the page address using
vmalloc_to_page() instead.
Signed-off-by: Roman Skakun <roman_skakun@epam.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
---
Hi, Christoph!
It's updated patch in accordance with your and Stefano
suggestions.
drivers/xen/swiotlb-xen.c | 7 +------
include/linux/dma-map-ops.h | 2 ++
kernel/dma/ops_helpers.c | 16 ++++++++++++++--
3 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 92ee6eea30cd..c2f612a10a95 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -337,7 +337,7 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
int order = get_order(size);
phys_addr_t phys;
u64 dma_mask = DMA_BIT_MASK(32);
- struct page *page;
+ struct page *page = cpu_addr_to_page(vaddr);
if (hwdev && hwdev->coherent_dma_mask)
dma_mask = hwdev->coherent_dma_mask;
@@ -349,11 +349,6 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
/* Convert the size to actually allocated. */
size = 1UL << (order + XEN_PAGE_SHIFT);
- if (is_vmalloc_addr(vaddr))
- page = vmalloc_to_page(vaddr);
- else
- page = virt_to_page(vaddr);
-
if (!WARN_ON((dev_addr + size - 1 > dma_mask) ||
range_straddles_page_boundary(phys, size)) &&
TestClearPageXenRemapped(page))
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index a5f89fc4d6df..ce0edb0bb603 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -226,6 +226,8 @@ struct page *dma_alloc_from_pool(struct device *dev, size_t size,
bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t));
bool dma_free_from_pool(struct device *dev, void *start, size_t size);
+struct page *cpu_addr_to_page(void *cpu_addr);
+
#ifdef CONFIG_ARCH_HAS_DMA_COHERENCE_H
#include <asm/dma-coherence.h>
#elif defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
index 910ae69cae77..472e861750d3 100644
--- a/kernel/dma/ops_helpers.c
+++ b/kernel/dma/ops_helpers.c
@@ -5,6 +5,17 @@
*/
#include <linux/dma-map-ops.h>
+/*
+ * This helper converts virtual address to page address.
+ */
+struct page *cpu_addr_to_page(void *cpu_addr)
+{
+ if (is_vmalloc_addr(cpu_addr))
+ return vmalloc_to_page(cpu_addr);
+ else
+ return virt_to_page(cpu_addr);
+}
+
/*
* Create scatter-list for the already allocated DMA buffer.
*/
@@ -12,7 +23,7 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
- struct page *page = virt_to_page(cpu_addr);
+ struct page *page = cpu_addr_to_page(cpu_addr);
int ret;
ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
@@ -32,6 +43,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long user_count = vma_pages(vma);
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long off = vma->vm_pgoff;
+ struct page *page = cpu_addr_to_page(cpu_addr);
int ret = -ENXIO;
vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
@@ -43,7 +55,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
return -ENXIO;
return remap_pfn_range(vma, vma->vm_start,
- page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
+ page_to_pfn(page) + vma->vm_pgoff,
user_count << PAGE_SHIFT, vma->vm_page_prot);
#else
return -ENXIO;
--
2.27.0
Technically this looks good. But given that exposing a helper
that does either vmalloc_to_page or virt_to_page is one of the
never ending MM discussions I don't want to get into that discussion
and just keep it local in the DMA code.
Are you fine with me applying this version?
---
From 40ac971eab89330d6153e7721e88acd2d98833f9 Mon Sep 17 00:00:00 2001
From: Roman Skakun <Roman_Skakun@epam.com>
Date: Fri, 16 Jul 2021 11:39:34 +0300
Subject: dma-mapping: handle vmalloc addresses in
dma_common_{mmap,get_sgtable}
xen-swiotlb can use vmalloc backed addresses for dma coherent allocations
and uses the common helpers. Properly handle them to unbreak Xen on
ARM platforms.
Fixes: 1b65c4e5a9af ("swiotlb-xen: use xen_alloc/free_coherent_pages")
Signed-off-by: Roman Skakun <roman_skakun@epam.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
[hch: split the patch, renamed the helpers]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
kernel/dma/ops_helpers.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
index 910ae69cae77..af4a6ef48ce0 100644
--- a/kernel/dma/ops_helpers.c
+++ b/kernel/dma/ops_helpers.c
@@ -5,6 +5,13 @@
*/
#include <linux/dma-map-ops.h>
+static struct page *dma_common_vaddr_to_page(void *cpu_addr)
+{
+ if (is_vmalloc_addr(cpu_addr))
+ return vmalloc_to_page(cpu_addr);
+ return virt_to_page(cpu_addr);
+}
+
/*
* Create scatter-list for the already allocated DMA buffer.
*/
@@ -12,7 +19,7 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
- struct page *page = virt_to_page(cpu_addr);
+ struct page *page = dma_common_vaddr_to_page(cpu_addr);
int ret;
ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
@@ -32,6 +39,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long user_count = vma_pages(vma);
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long off = vma->vm_pgoff;
+ struct page *page = dma_common_vaddr_to_page(cpu_addr);
int ret = -ENXIO;
vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
@@ -43,7 +51,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
return -ENXIO;
return remap_pfn_range(vma, vma->vm_start,
- page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
+ page_to_pfn(page) + vma->vm_pgoff,
user_count << PAGE_SHIFT, vma->vm_page_prot);
#else
return -ENXIO;
--
2.30.2
> Technically this looks good. But given that exposing a helper
> that does either vmalloc_to_page or virt_to_page is one of the
> never ending MM discussions I don't want to get into that discussion
> and just keep it local in the DMA code.
>
> Are you fine with me applying this version?
Looks good to me, thanks!
But, Stefano asked me about using created helper in the
xen_swiotlb_free_coherent()
and I created a patch according to this mention.
We can merge this patch and create a new one for
xen_swiotlb_free_coherent() later.
пт, 16 июл. 2021 г. в 12:35, Christoph Hellwig <hch@lst.de>:
>
> Technically this looks good. But given that exposing a helper
> that does either vmalloc_to_page or virt_to_page is one of the
> never ending MM discussions I don't want to get into that discussion
> and just keep it local in the DMA code.
>
> Are you fine with me applying this version?
>
> ---
> From 40ac971eab89330d6153e7721e88acd2d98833f9 Mon Sep 17 00:00:00 2001
> From: Roman Skakun <Roman_Skakun@epam.com>
> Date: Fri, 16 Jul 2021 11:39:34 +0300
> Subject: dma-mapping: handle vmalloc addresses in
> dma_common_{mmap,get_sgtable}
>
> xen-swiotlb can use vmalloc backed addresses for dma coherent allocations
> and uses the common helpers. Properly handle them to unbreak Xen on
> ARM platforms.
>
> Fixes: 1b65c4e5a9af ("swiotlb-xen: use xen_alloc/free_coherent_pages")
> Signed-off-by: Roman Skakun <roman_skakun@epam.com>
> Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
> [hch: split the patch, renamed the helpers]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> kernel/dma/ops_helpers.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
> index 910ae69cae77..af4a6ef48ce0 100644
> --- a/kernel/dma/ops_helpers.c
> +++ b/kernel/dma/ops_helpers.c
> @@ -5,6 +5,13 @@
> */
> #include <linux/dma-map-ops.h>
>
> +static struct page *dma_common_vaddr_to_page(void *cpu_addr)
> +{
> + if (is_vmalloc_addr(cpu_addr))
> + return vmalloc_to_page(cpu_addr);
> + return virt_to_page(cpu_addr);
> +}
> +
> /*
> * Create scatter-list for the already allocated DMA buffer.
> */
> @@ -12,7 +19,7 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
> void *cpu_addr, dma_addr_t dma_addr, size_t size,
> unsigned long attrs)
> {
> - struct page *page = virt_to_page(cpu_addr);
> + struct page *page = dma_common_vaddr_to_page(cpu_addr);
> int ret;
>
> ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> @@ -32,6 +39,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
> unsigned long user_count = vma_pages(vma);
> unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> unsigned long off = vma->vm_pgoff;
> + struct page *page = dma_common_vaddr_to_page(cpu_addr);
> int ret = -ENXIO;
>
> vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
> @@ -43,7 +51,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
> return -ENXIO;
>
> return remap_pfn_range(vma, vma->vm_start,
> - page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
> + page_to_pfn(page) + vma->vm_pgoff,
> user_count << PAGE_SHIFT, vma->vm_page_prot);
> #else
> return -ENXIO;
> --
> 2.30.2
>
--
Best Regards, Roman.
On Fri, 16 Jul 2021, Roman Skakun wrote:
> > Technically this looks good. But given that exposing a helper
> > that does either vmalloc_to_page or virt_to_page is one of the
> > never ending MM discussions I don't want to get into that discussion
> > and just keep it local in the DMA code.
> >
> > Are you fine with me applying this version?
>
> Looks good to me, thanks!
> But, Stefano asked me about using created helper in the
> xen_swiotlb_free_coherent()
> and I created a patch according to this mention.
>
> We can merge this patch and create a new one for
> xen_swiotlb_free_coherent() later.
Yeah, no worries, I didn't know that exposing dma_common_vaddr_to_page
was problematic.
This patch is fine by me.
> пт, 16 июл. 2021 г. в 12:35, Christoph Hellwig <hch@lst.de>:
> >
> > Technically this looks good. But given that exposing a helper
> > that does either vmalloc_to_page or virt_to_page is one of the
> > never ending MM discussions I don't want to get into that discussion
> > and just keep it local in the DMA code.
> >
> > Are you fine with me applying this version?
> >
> > ---
> > From 40ac971eab89330d6153e7721e88acd2d98833f9 Mon Sep 17 00:00:00 2001
> > From: Roman Skakun <Roman_Skakun@epam.com>
> > Date: Fri, 16 Jul 2021 11:39:34 +0300
> > Subject: dma-mapping: handle vmalloc addresses in
> > dma_common_{mmap,get_sgtable}
> >
> > xen-swiotlb can use vmalloc backed addresses for dma coherent allocations
> > and uses the common helpers. Properly handle them to unbreak Xen on
> > ARM platforms.
> >
> > Fixes: 1b65c4e5a9af ("swiotlb-xen: use xen_alloc/free_coherent_pages")
> > Signed-off-by: Roman Skakun <roman_skakun@epam.com>
> > Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
> > [hch: split the patch, renamed the helpers]
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > ---
> > kernel/dma/ops_helpers.c | 12 ++++++++++--
> > 1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
> > index 910ae69cae77..af4a6ef48ce0 100644
> > --- a/kernel/dma/ops_helpers.c
> > +++ b/kernel/dma/ops_helpers.c
> > @@ -5,6 +5,13 @@
> > */
> > #include <linux/dma-map-ops.h>
> >
> > +static struct page *dma_common_vaddr_to_page(void *cpu_addr)
> > +{
> > + if (is_vmalloc_addr(cpu_addr))
> > + return vmalloc_to_page(cpu_addr);
> > + return virt_to_page(cpu_addr);
> > +}
> > +
> > /*
> > * Create scatter-list for the already allocated DMA buffer.
> > */
> > @@ -12,7 +19,7 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
> > void *cpu_addr, dma_addr_t dma_addr, size_t size,
> > unsigned long attrs)
> > {
> > - struct page *page = virt_to_page(cpu_addr);
> > + struct page *page = dma_common_vaddr_to_page(cpu_addr);
> > int ret;
> >
> > ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> > @@ -32,6 +39,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
> > unsigned long user_count = vma_pages(vma);
> > unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> > unsigned long off = vma->vm_pgoff;
> > + struct page *page = dma_common_vaddr_to_page(cpu_addr);
> > int ret = -ENXIO;
> >
> > vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
> > @@ -43,7 +51,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
> > return -ENXIO;
> >
> > return remap_pfn_range(vma, vma->vm_start,
> > - page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
> > + page_to_pfn(page) + vma->vm_pgoff,
> > user_count << PAGE_SHIFT, vma->vm_page_prot);
> > #else
> > return -ENXIO;
> > --
> > 2.30.2
> >
>
>
> --
> Best Regards, Roman.
>
> We can merge this patch and create a new one for
> xen_swiotlb_free_coherent() later.
> Yeah, no worries, I didn't know that exposing dma_common_vaddr_to_page
> was problematic.
>
> This patch is fine by me.
Good. I'm agreed too. Waiting for Christoph.
пт, 16 июл. 2021 г. в 18:29, Stefano Stabellini <sstabellini@kernel.org>:
>
> On Fri, 16 Jul 2021, Roman Skakun wrote:
> > > Technically this looks good. But given that exposing a helper
> > > that does either vmalloc_to_page or virt_to_page is one of the
> > > never ending MM discussions I don't want to get into that discussion
> > > and just keep it local in the DMA code.
> > >
> > > Are you fine with me applying this version?
> >
> > Looks good to me, thanks!
> > But, Stefano asked me about using created helper in the
> > xen_swiotlb_free_coherent()
> > and I created a patch according to this mention.
> >
> > We can merge this patch and create a new one for
> > xen_swiotlb_free_coherent() later.
>
> Yeah, no worries, I didn't know that exposing dma_common_vaddr_to_page
> was problematic.
>
> This patch is fine by me.
>
>
> > пт, 16 июл. 2021 г. в 12:35, Christoph Hellwig <hch@lst.de>:
> > >
> > > Technically this looks good. But given that exposing a helper
> > > that does either vmalloc_to_page or virt_to_page is one of the
> > > never ending MM discussions I don't want to get into that discussion
> > > and just keep it local in the DMA code.
> > >
> > > Are you fine with me applying this version?
> > >
> > > ---
> > > From 40ac971eab89330d6153e7721e88acd2d98833f9 Mon Sep 17 00:00:00 2001
> > > From: Roman Skakun <Roman_Skakun@epam.com>
> > > Date: Fri, 16 Jul 2021 11:39:34 +0300
> > > Subject: dma-mapping: handle vmalloc addresses in
> > > dma_common_{mmap,get_sgtable}
> > >
> > > xen-swiotlb can use vmalloc backed addresses for dma coherent allocations
> > > and uses the common helpers. Properly handle them to unbreak Xen on
> > > ARM platforms.
> > >
> > > Fixes: 1b65c4e5a9af ("swiotlb-xen: use xen_alloc/free_coherent_pages")
> > > Signed-off-by: Roman Skakun <roman_skakun@epam.com>
> > > Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
> > > [hch: split the patch, renamed the helpers]
> > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > > ---
> > > kernel/dma/ops_helpers.c | 12 ++++++++++--
> > > 1 file changed, 10 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
> > > index 910ae69cae77..af4a6ef48ce0 100644
> > > --- a/kernel/dma/ops_helpers.c
> > > +++ b/kernel/dma/ops_helpers.c
> > > @@ -5,6 +5,13 @@
> > > */
> > > #include <linux/dma-map-ops.h>
> > >
> > > +static struct page *dma_common_vaddr_to_page(void *cpu_addr)
> > > +{
> > > + if (is_vmalloc_addr(cpu_addr))
> > > + return vmalloc_to_page(cpu_addr);
> > > + return virt_to_page(cpu_addr);
> > > +}
> > > +
> > > /*
> > > * Create scatter-list for the already allocated DMA buffer.
> > > */
> > > @@ -12,7 +19,7 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
> > > void *cpu_addr, dma_addr_t dma_addr, size_t size,
> > > unsigned long attrs)
> > > {
> > > - struct page *page = virt_to_page(cpu_addr);
> > > + struct page *page = dma_common_vaddr_to_page(cpu_addr);
> > > int ret;
> > >
> > > ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> > > @@ -32,6 +39,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
> > > unsigned long user_count = vma_pages(vma);
> > > unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> > > unsigned long off = vma->vm_pgoff;
> > > + struct page *page = dma_common_vaddr_to_page(cpu_addr);
> > > int ret = -ENXIO;
> > >
> > > vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
> > > @@ -43,7 +51,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
> > > return -ENXIO;
> > >
> > > return remap_pfn_range(vma, vma->vm_start,
> > > - page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
> > > + page_to_pfn(page) + vma->vm_pgoff,
> > > user_count << PAGE_SHIFT, vma->vm_page_prot);
> > > #else
> > > return -ENXIO;
> > > --
> > > 2.30.2
> > >
> >
> >
> > --
> > Best Regards, Roman.
> >
--
Best Regards, Roman.
On Sat, Jul 17, 2021 at 11:39:21AM +0300, Roman Skakun wrote: > > We can merge this patch and create a new one for > > xen_swiotlb_free_coherent() later. > > Yeah, no worries, I didn't know that exposing dma_common_vaddr_to_page > > was problematic. > > > > This patch is fine by me. > > Good. I'm agreed too. Waiting for Christoph. Fine with. I've queued up the modified patch.
> Fine with. I've queued up the modified patch. Good. Thanks! > > On Sat, Jul 17, 2021 at 11:39:21AM +0300, Roman Skakun wrote: > > > We can merge this patch and create a new one for > > > xen_swiotlb_free_coherent() later. > > > Yeah, no worries, I didn't know that exposing dma_common_vaddr_to_page > > > was problematic. > > > > > > This patch is fine by me. > > > > Good. I'm agreed too. Waiting for Christoph. > > Fine with. I've queued up the modified patch. -- Best Regards, Roman.
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