* [PATCH v6 14/20] dma-direct: return struct page from dma_direct_alloc_from_pool()
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, stable, Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Commit 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool
helper") changed dma_direct_alloc_from_pool() to return the CPU address
from dma_alloc_from_pool(). That fits dma_direct_alloc(), but
dma_direct_alloc_pages() also uses the helper and expects a struct page *.
Fix this by making dma_direct_alloc_from_pool() return the struct page *
again, and pass the CPU address back through an out-parameter for the
dma_direct_alloc() caller.
Fixes: 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool helper")
Cc: stable@vger.kernel.org
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
kernel/dma/direct.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 4e446aa4130e..e0ab9ff3f1d6 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -157,24 +157,24 @@ static bool dma_direct_use_pool(struct device *dev, gfp_t gfp)
return !gfpflags_allow_blocking(gfp) && !is_swiotlb_for_alloc(dev);
}
-static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
- dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+static struct page *dma_direct_alloc_from_pool(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, void **cpu_addr, gfp_t gfp,
+ unsigned long attrs)
{
struct page *page;
u64 phys_limit;
- void *ret;
if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)))
return NULL;
gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit);
- page = dma_alloc_from_pool(dev, size, &ret, gfp, attrs,
+ page = dma_alloc_from_pool(dev, size, cpu_addr, gfp, attrs,
dma_coherent_ok);
if (!page)
return NULL;
*dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
!!(attrs & DMA_ATTR_CC_SHARED));
- return ret;
+ return page;
}
static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
@@ -270,9 +270,12 @@ void *dma_direct_alloc(struct device *dev, size_t size,
* the atomic pools instead if we aren't allowed block.
*/
if ((remap || (attrs & DMA_ATTR_CC_SHARED)) &&
- dma_direct_use_pool(dev, gfp))
- return dma_direct_alloc_from_pool(dev, size, dma_handle,
- gfp, attrs);
+ dma_direct_use_pool(dev, gfp)) {
+ page = dma_direct_alloc_from_pool(dev, size,
+ dma_handle, &cpu_addr,
+ gfp, attrs);
+ return page ? cpu_addr : NULL;
+ }
if (is_swiotlb_for_alloc(dev)) {
page = dma_direct_alloc_swiotlb(dev, size, attrs);
@@ -445,7 +448,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
if ((attrs & DMA_ATTR_CC_SHARED) && dma_direct_use_pool(dev, gfp))
return dma_direct_alloc_from_pool(dev, size, dma_handle,
- gfp, attrs);
+ &cpu_addr, gfp, attrs);
if (is_swiotlb_for_alloc(dev)) {
page = dma_direct_alloc_swiotlb(dev, size, attrs);
--
2.43.0
^ permalink raw reply related
* [PATCH v6 13/20] dma-direct: rename ret to cpu_addr in alloc helpers
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
ret in dma_direct_alloc() and dma_direct_alloc_pages() holds the returned
CPU mapping, not a generic return value. Rename it to cpu_addr and update
the remaining uses to match.
This makes the allocation paths easier to follow and keeps the local naming
consistent with what the variable actually represents.
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
kernel/dma/direct.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index aa3489aa10a0..4e446aa4130e 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -204,7 +204,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
bool mark_mem_decrypt = false;
bool allow_highmem = true;
struct page *page;
- void *ret;
+ void *cpu_addr;
/*
* DMA_ATTR_CC_SHARED is not a caller-visible dma_alloc_*()
@@ -318,34 +318,33 @@ void *dma_direct_alloc(struct device *dev, size_t size,
arch_dma_prep_coherent(page, size);
/* create a coherent mapping */
- ret = dma_common_contiguous_remap(page, size, prot,
- __builtin_return_address(0));
- if (!ret)
+ cpu_addr = dma_common_contiguous_remap(page, size, prot,
+ __builtin_return_address(0));
+ if (!cpu_addr)
goto out_encrypt_pages;
} else {
- ret = page_address(page);
+ cpu_addr = page_address(page);
}
- memset(ret, 0, size);
+ memset(cpu_addr, 0, size);
if (set_uncached) {
void *uncached_cpu_addr;
arch_dma_prep_coherent(page, size);
- uncached_cpu_addr = arch_dma_set_uncached(ret, size);
+ uncached_cpu_addr = arch_dma_set_uncached(cpu_addr, size);
if (IS_ERR(uncached_cpu_addr))
goto out_free_remap_pages;
- ret = uncached_cpu_addr;
+ cpu_addr = uncached_cpu_addr;
}
*dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
!!(attrs & DMA_ATTR_CC_SHARED));
- return ret;
-
+ return cpu_addr;
out_free_remap_pages:
if (remap)
- dma_common_free_remap(ret, size);
+ dma_common_free_remap(cpu_addr, size);
out_encrypt_pages:
if (mark_mem_decrypt &&
@@ -439,7 +438,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
{
unsigned long attrs = 0;
struct page *page;
- void *ret;
+ void *cpu_addr;
if (force_dma_unencrypted(dev))
attrs |= DMA_ATTR_CC_SHARED;
@@ -453,7 +452,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
if (!page)
return NULL;
- ret = page_address(page);
+ cpu_addr = page_address(page);
goto setup_page;
}
@@ -461,11 +460,11 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
if (!page)
return NULL;
- ret = page_address(page);
- if ((attrs & DMA_ATTR_CC_SHARED) && dma_set_decrypted(dev, ret, size))
+ cpu_addr = page_address(page);
+ if ((attrs & DMA_ATTR_CC_SHARED) && dma_set_decrypted(dev, cpu_addr, size))
goto out_leak_pages;
setup_page:
- memset(ret, 0, size);
+ memset(cpu_addr, 0, size);
*dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
!!(attrs & DMA_ATTR_CC_SHARED));
return page;
--
2.43.0
^ permalink raw reply related
* [PATCH v6 12/20] dma-pool: fix page leak in atomic_pool_expand() cleanup
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
atomic_pool_expand() frees the allocated pages from the remove_mapping
error path only when CONFIG_DMA_DIRECT_REMAP is enabled.
When CONFIG_DMA_DIRECT_REMAP is disabled, failures after page allocation,
such as gen_pool_add_virt(), jump to remove_mapping and return without
freeing the pages.
Move __free_pages(page, order) out of the CONFIG_DMA_DIRECT_REMAP block so
that cleanup paths always release the allocation.
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
kernel/dma/pool.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index be78474a6c49..e7df8d279e75 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -146,9 +146,9 @@ static int atomic_pool_expand(struct dma_gen_pool *dma_pool, size_t pool_size,
#ifdef CONFIG_DMA_DIRECT_REMAP
dma_common_free_remap(addr, pool_size);
free_page:
+#endif
if (!leak_pages)
__free_pages(page, order);
-#endif
out:
return ret;
}
--
2.43.0
^ permalink raw reply related
* [PATCH v6 11/20] dma-direct: select DMA address encoding from DMA_ATTR_CC_SHARED
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Make the dma-direct helpers derive the DMA address encoding from
DMA_ATTR_CC_SHARED instead of implicitly relying on
force_dma_unencrypted() inside phys_to_dma_direct()
Pass an explicit unencrypted/decrypted state into phys_to_dma_direct(),
make the alloc paths return DMA addresses that match the requested buffer
encryption state. Also only call dma_set_decrypted() when
DMA_ATTR_CC_SHARED is actually set.
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
kernel/dma/direct.c | 42 +++++++++++++++++++++++++-----------------
1 file changed, 25 insertions(+), 17 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 9ce4fff6c112..aa3489aa10a0 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -24,11 +24,11 @@
u64 zone_dma_limit __ro_after_init = DMA_BIT_MASK(24);
static inline dma_addr_t phys_to_dma_direct(struct device *dev,
- phys_addr_t phys)
+ phys_addr_t phys, bool unencrypted)
{
- if (force_dma_unencrypted(dev))
+ if (unencrypted)
return phys_to_dma_unencrypted(dev, phys);
- return phys_to_dma(dev, phys);
+ return phys_to_dma_encrypted(dev, phys);
}
static inline struct page *dma_direct_to_page(struct device *dev,
@@ -39,8 +39,9 @@ static inline struct page *dma_direct_to_page(struct device *dev,
u64 dma_direct_get_required_mask(struct device *dev)
{
+ bool require_decrypted = force_dma_unencrypted(dev);
phys_addr_t phys = ((phys_addr_t)max_pfn << PAGE_SHIFT) - 1;
- u64 max_dma = phys_to_dma_direct(dev, phys);
+ u64 max_dma = phys_to_dma_direct(dev, phys, require_decrypted);
return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
}
@@ -69,7 +70,8 @@ static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 *phys_limit)
bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
{
- dma_addr_t dma_addr = phys_to_dma_direct(dev, phys);
+ bool require_decrypted = force_dma_unencrypted(dev);
+ dma_addr_t dma_addr = phys_to_dma_direct(dev, phys, require_decrypted);
if (dma_addr == DMA_MAPPING_ERROR)
return false;
@@ -79,17 +81,18 @@ bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
static int dma_set_decrypted(struct device *dev, void *vaddr, size_t size)
{
- if (!force_dma_unencrypted(dev))
- return 0;
- return set_memory_decrypted((unsigned long)vaddr, PFN_UP(size));
+ int ret;
+
+ ret = set_memory_decrypted((unsigned long)vaddr, PFN_UP(size));
+ if (ret)
+ pr_warn_ratelimited("leaking DMA memory that can't be decrypted\n");
+ return ret;
}
static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size)
{
int ret;
- if (!force_dma_unencrypted(dev))
- return 0;
ret = set_memory_encrypted((unsigned long)vaddr, PFN_UP(size));
if (ret)
pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n");
@@ -169,7 +172,8 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
dma_coherent_ok);
if (!page)
return NULL;
- *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ *dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
+ !!(attrs & DMA_ATTR_CC_SHARED));
return ret;
}
@@ -185,9 +189,11 @@ static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
/* remove any dirty cache lines on the kernel alias */
if (!PageHighMem(page))
arch_dma_prep_coherent(page, size);
-
- /* return the page pointer as the opaque cookie */
- *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ /*
+ * return the page pointer as the opaque cookie.
+ * Never used for unencrypted allocation
+ */
+ *dma_handle = phys_to_dma_encrypted(dev, page_to_phys(page));
return page;
}
@@ -332,7 +338,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
ret = uncached_cpu_addr;
}
- *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ *dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
+ !!(attrs & DMA_ATTR_CC_SHARED));
return ret;
@@ -455,11 +462,12 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
return NULL;
ret = page_address(page);
- if (dma_set_decrypted(dev, ret, size))
+ if ((attrs & DMA_ATTR_CC_SHARED) && dma_set_decrypted(dev, ret, size))
goto out_leak_pages;
setup_page:
memset(ret, 0, size);
- *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ *dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
+ !!(attrs & DMA_ATTR_CC_SHARED));
return page;
out_leak_pages:
return NULL;
--
2.43.0
^ permalink raw reply related
* [PATCH v6 10/20] dma-direct: set decrypted flag for remapped DMA allocations
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Devices that are DMA non-coherent and require a remap were skipping
dma_set_decrypted(), leaving DMA buffers encrypted even when the device
requires unencrypted access. Move the call after the if (remap) branch
so that both the direct and remapped allocation paths correctly mark the
allocation as decrypted (or fail cleanly) before use.
Fix dma_direct_alloc() and dma_direct_free() to apply set_memory_*() to
the linear-map alias of the backing pages instead of the remapped CPU
address. Also disallow highmem pages for DMA_ATTR_CC_SHARED, because
highmem buffers do not provide a usable linear-map address.
Fixes: f3c962226dbe ("dma-direct: clean up the remapping checks in dma_direct_alloc")
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
kernel/dma/direct.c | 55 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 44 insertions(+), 11 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 6d0ce3cfd8cc..9ce4fff6c112 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -196,6 +196,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
{
bool remap = false, set_uncached = false;
bool mark_mem_decrypt = false;
+ bool allow_highmem = true;
struct page *page;
void *ret;
@@ -214,6 +215,15 @@ void *dma_direct_alloc(struct device *dev, size_t size,
mark_mem_decrypt = true;
}
+ if (attrs & DMA_ATTR_CC_SHARED)
+ /*
+ * Unencrypted/shared DMA requires a linear-mapped buffer
+ * address to look up the PFN and set architecture-required PFN
+ * attributes. This is not possible with HighMem. Avoid HighMem
+ * allocation.
+ */
+ allow_highmem = false;
+
size = PAGE_ALIGN(size);
if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN;
@@ -272,7 +282,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
}
/* we always manually zero the memory once we are done */
- page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true);
+ page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, allow_highmem);
if (!page)
return NULL;
@@ -287,6 +297,14 @@ void *dma_direct_alloc(struct device *dev, size_t size,
set_uncached = false;
}
+ if (mark_mem_decrypt) {
+ void *lm_addr;
+
+ lm_addr = page_address(page);
+ if (set_memory_decrypted((unsigned long)lm_addr, PFN_UP(size)))
+ goto out_leak_pages;
+ }
+
if (remap) {
pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs);
@@ -297,29 +315,36 @@ void *dma_direct_alloc(struct device *dev, size_t size,
ret = dma_common_contiguous_remap(page, size, prot,
__builtin_return_address(0));
if (!ret)
- goto out_free_pages;
+ goto out_encrypt_pages;
} else {
ret = page_address(page);
- if (mark_mem_decrypt && dma_set_decrypted(dev, ret, size))
- goto out_leak_pages;
}
memset(ret, 0, size);
if (set_uncached) {
+ void *uncached_cpu_addr;
+
arch_dma_prep_coherent(page, size);
- ret = arch_dma_set_uncached(ret, size);
- if (IS_ERR(ret))
- goto out_encrypt_pages;
+ uncached_cpu_addr = arch_dma_set_uncached(ret, size);
+ if (IS_ERR(uncached_cpu_addr))
+ goto out_free_remap_pages;
+ ret = uncached_cpu_addr;
}
*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
return ret;
+
+out_free_remap_pages:
+ if (remap)
+ dma_common_free_remap(ret, size);
+
out_encrypt_pages:
- if (mark_mem_decrypt && dma_set_encrypted(dev, page_address(page), size))
- return NULL;
-out_free_pages:
+ if (mark_mem_decrypt &&
+ dma_set_encrypted(dev, page_address(page), size))
+ goto out_leak_pages;
+
if (!swiotlb_free(dev, page, size))
dma_free_contiguous(dev, page, size);
return NULL;
@@ -384,8 +409,16 @@ void dma_direct_free(struct device *dev, size_t size,
} else {
if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED))
arch_dma_clear_uncached(cpu_addr, size);
- if (mark_mem_encrypted && dma_set_encrypted(dev, cpu_addr, size))
+ }
+
+ if (mark_mem_encrypted) {
+ void *lm_addr;
+
+ lm_addr = phys_to_virt(phys);
+ if (set_memory_encrypted((unsigned long)lm_addr, PFN_UP(size))) {
+ pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n");
return;
+ }
}
if (swiotlb_pool)
--
2.43.0
^ permalink raw reply related
* [PATCH v6 09/20] dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Teach dma_direct_map_phys() to select the DMA address encoding based on
DMA_ATTR_CC_SHARED.
Use phys_to_dma_unencrypted() for decrypted mappings and
phys_to_dma_encrypted() otherwise. If a device requires unencrypted DMA
but the source physical address is still encrypted, force the mapping
through swiotlb so the DMA address and backing memory attributes remain
consistent.
Update the arm64, x86, s390 and powerpc secure-guest setup to not use
swiotlb force option
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
Changes from v3:
* Handle DMA_ATTR_MMIO
---
arch/arm64/mm/init.c | 4 +--
arch/powerpc/platforms/pseries/svm.c | 2 +-
arch/s390/mm/init.c | 2 +-
arch/x86/kernel/pci-dma.c | 4 +--
kernel/dma/direct.c | 4 ++-
kernel/dma/direct.h | 45 +++++++++++++++-------------
6 files changed, 31 insertions(+), 30 deletions(-)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 97987f850a33..acf67c7064db 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -338,10 +338,8 @@ void __init arch_mm_preinit(void)
unsigned int flags = SWIOTLB_VERBOSE;
bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit);
- if (is_realm_world()) {
+ if (is_realm_world())
swiotlb = true;
- flags |= SWIOTLB_FORCE;
- }
if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb) {
/*
diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
index 384c9dc1899a..7a403dbd35ee 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -29,7 +29,7 @@ static int __init init_svm(void)
* need to use the SWIOTLB buffer for DMA even if dma_capable() says
* otherwise.
*/
- ppc_swiotlb_flags |= SWIOTLB_ANY | SWIOTLB_FORCE;
+ ppc_swiotlb_flags |= SWIOTLB_ANY;
/* Share the SWIOTLB buffer with the host. */
swiotlb_update_mem_attributes();
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index ad3c6d92b801..581af1483c42 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -163,7 +163,7 @@ static void __init pv_init(void)
virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
/* make sure bounce buffers are shared */
- swiotlb_init(true, SWIOTLB_FORCE | SWIOTLB_VERBOSE);
+ swiotlb_init(true, SWIOTLB_VERBOSE);
swiotlb_update_mem_attributes();
}
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 6267363e0189..75cf8f6ae8cd 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -59,10 +59,8 @@ static void __init pci_swiotlb_detect(void)
* bounce buffers as the hypervisor can't access arbitrary VM memory
* that is not explicitly shared with it.
*/
- if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
+ if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
x86_swiotlb_enable = true;
- x86_swiotlb_flags |= SWIOTLB_FORCE;
- }
}
#else
static inline void __init pci_swiotlb_detect(void)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index e4cba322386d..6d0ce3cfd8cc 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -702,8 +702,10 @@ size_t dma_direct_max_mapping_size(struct device *dev)
{
/* If SWIOTLB is active, use its maximum mapping size */
if (is_swiotlb_active(dev) &&
- (dma_addressing_limited(dev) || is_swiotlb_force_bounce(dev)))
+ (dma_addressing_limited(dev) || is_swiotlb_force_bounce(dev) ||
+ force_dma_unencrypted(dev)))
return swiotlb_max_mapping_size(dev);
+
return SIZE_MAX;
}
diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
index e05dc7649366..f3fc28f352ba 100644
--- a/kernel/dma/direct.h
+++ b/kernel/dma/direct.h
@@ -88,37 +88,40 @@ static inline dma_addr_t dma_direct_map_phys(struct device *dev,
{
dma_addr_t dma_addr;
+ /*
+ * For a device requiring unencrypted DMA, MMIO memory is treated
+ * as shared by default.
+ */
+ if (force_dma_unencrypted(dev) && (attrs & DMA_ATTR_MMIO))
+ attrs |= DMA_ATTR_CC_SHARED;
+
if (is_swiotlb_force_bounce(dev)) {
- if (!(attrs & DMA_ATTR_CC_SHARED)) {
- if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT))
- return DMA_MAPPING_ERROR;
+ if (attrs & (DMA_ATTR_MMIO | DMA_ATTR_REQUIRE_COHERENT))
+ return DMA_MAPPING_ERROR;
- return swiotlb_map(dev, phys, size, dir, attrs);
- }
- } else if (attrs & DMA_ATTR_CC_SHARED) {
- return DMA_MAPPING_ERROR;
+ return swiotlb_map(dev, phys, size, dir, attrs);
}
- if (attrs & DMA_ATTR_MMIO) {
- dma_addr = phys;
- if (unlikely(!dma_capable(dev, dma_addr, size, false, attrs)))
- goto err_overflow;
- } else if (attrs & DMA_ATTR_CC_SHARED) {
+ if (attrs & DMA_ATTR_CC_SHARED)
dma_addr = phys_to_dma_unencrypted(dev, phys);
+ else
+ dma_addr = phys_to_dma_encrypted(dev, phys);
+
+ if (attrs & DMA_ATTR_MMIO) {
if (unlikely(!dma_capable(dev, dma_addr, size, false, attrs)))
goto err_overflow;
- } else {
- dma_addr = phys_to_dma(dev, phys);
- if (unlikely(!dma_capable(dev, dma_addr, size, true, attrs)) ||
- dma_kmalloc_needs_bounce(dev, size, dir)) {
- if (is_swiotlb_active(dev) &&
- !(attrs & DMA_ATTR_REQUIRE_COHERENT))
- return swiotlb_map(dev, phys, size, dir, attrs);
+ goto dma_mapped;
+ }
- goto err_overflow;
- }
+ if (unlikely(!dma_capable(dev, dma_addr, size, true, attrs)) ||
+ dma_kmalloc_needs_bounce(dev, size, dir)) {
+ if (is_swiotlb_active(dev) &&
+ !(attrs & DMA_ATTR_REQUIRE_COHERENT))
+ return swiotlb_map(dev, phys, size, dir, attrs);
+ goto err_overflow;
}
+dma_mapped:
if (!dev_is_dma_coherent(dev) &&
!(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) {
arch_sync_dma_for_device(phys, size, dir);
--
2.43.0
^ permalink raw reply related
* [PATCH v6 08/20] dma-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Teach dma_capable() about DMA_ATTR_CC_SHARED so the capability
check can reject encrypted DMA addresses for devices that require
unencrypted/shared DMA.
Also propagate DMA_ATTR_CC_SHARED in swiotlb_map() when the selected
SWIOTLB pool is decrypted so the capability check sees the correct DMA
address attribute.
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
arch/x86/kernel/amd_gart_64.c | 30 ++++++++++++++++--------------
drivers/xen/swiotlb-xen.c | 6 +++---
include/linux/dma-direct.h | 10 +++++++++-
kernel/dma/direct.h | 6 +++---
kernel/dma/swiotlb.c | 2 +-
5 files changed, 32 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index e8000a56732e..b5f1f031d45b 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -180,22 +180,23 @@ static void iommu_full(struct device *dev, size_t size, int dir)
}
static inline int
-need_iommu(struct device *dev, unsigned long addr, size_t size)
+need_iommu(struct device *dev, unsigned long addr, size_t size, unsigned long attrs)
{
- return force_iommu || !dma_capable(dev, addr, size, true);
+ return force_iommu || !dma_capable(dev, addr, size, true, attrs);
}
static inline int
-nonforced_iommu(struct device *dev, unsigned long addr, size_t size)
+nonforced_iommu(struct device *dev, unsigned long addr, size_t size,
+ unsigned long attrs)
{
- return !dma_capable(dev, addr, size, true);
+ return !dma_capable(dev, addr, size, true, attrs);
}
/* Map a single continuous physical area into the IOMMU.
* Caller needs to check if the iommu is needed and flush.
*/
static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
- size_t size, int dir, unsigned long align_mask)
+ size_t size, int dir, unsigned long align_mask, unsigned long attrs)
{
unsigned long npages = iommu_num_pages(phys_mem, size, PAGE_SIZE);
unsigned long iommu_page;
@@ -206,7 +207,7 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
iommu_page = alloc_iommu(dev, npages, align_mask);
if (iommu_page == -1) {
- if (!nonforced_iommu(dev, phys_mem, size))
+ if (!nonforced_iommu(dev, phys_mem, size, attrs))
return phys_mem;
if (panic_on_overflow)
panic("dma_map_area overflow %lu bytes\n", size);
@@ -231,10 +232,10 @@ static dma_addr_t gart_map_phys(struct device *dev, phys_addr_t paddr,
if (unlikely(attrs & DMA_ATTR_MMIO))
return DMA_MAPPING_ERROR;
- if (!need_iommu(dev, paddr, size))
+ if (!need_iommu(dev, paddr, size, attrs))
return paddr;
- bus = dma_map_area(dev, paddr, size, dir, 0);
+ bus = dma_map_area(dev, paddr, size, dir, 0, attrs);
flush_gart();
return bus;
@@ -289,7 +290,7 @@ static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
/* Fallback for dma_map_sg in case of overflow */
static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
- int nents, int dir)
+ int nents, int dir, unsigned long attrs)
{
struct scatterlist *s;
int i;
@@ -301,8 +302,8 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
for_each_sg(sg, s, nents, i) {
unsigned long addr = sg_phys(s);
- if (nonforced_iommu(dev, addr, s->length)) {
- addr = dma_map_area(dev, addr, s->length, dir, 0);
+ if (nonforced_iommu(dev, addr, s->length, attrs)) {
+ addr = dma_map_area(dev, addr, s->length, dir, 0, attrs);
if (addr == DMA_MAPPING_ERROR) {
if (i > 0)
gart_unmap_sg(dev, sg, i, dir, 0);
@@ -401,7 +402,7 @@ static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
s->dma_address = addr;
BUG_ON(s->length == 0);
- nextneed = need_iommu(dev, addr, s->length);
+ nextneed = need_iommu(dev, addr, s->length, attrs);
/* Handle the previous not yet processed entries */
if (i > start) {
@@ -449,7 +450,7 @@ static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
/* When it was forced or merged try again in a dumb way */
if (force_iommu || iommu_merge) {
- out = dma_map_sg_nonforce(dev, sg, nents, dir);
+ out = dma_map_sg_nonforce(dev, sg, nents, dir, attrs);
if (out > 0)
return out;
}
@@ -473,7 +474,8 @@ gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
return vaddr;
*dma_addr = dma_map_area(dev, virt_to_phys(vaddr), size,
- DMA_BIDIRECTIONAL, (1UL << get_order(size)) - 1);
+ DMA_BIDIRECTIONAL,
+ (1UL << get_order(size)) - 1, attrs);
flush_gart();
if (unlikely(*dma_addr == DMA_MAPPING_ERROR))
goto out_free;
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 8c4abe65cd49..e2538824ef52 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -212,7 +212,7 @@ static dma_addr_t xen_swiotlb_map_phys(struct device *dev, phys_addr_t phys,
BUG_ON(dir == DMA_NONE);
if (attrs & DMA_ATTR_MMIO) {
- if (unlikely(!dma_capable(dev, phys, size, false))) {
+ if (unlikely(!dma_capable(dev, phys, size, false, attrs))) {
dev_err_once(
dev,
"DMA addr %pa+%zu overflow (mask %llx, bus limit %llx).\n",
@@ -231,7 +231,7 @@ static dma_addr_t xen_swiotlb_map_phys(struct device *dev, phys_addr_t phys,
* we can safely return the device addr and not worry about bounce
* buffering it.
*/
- if (dma_capable(dev, dev_addr, size, true) &&
+ if (dma_capable(dev, dev_addr, size, true, attrs) &&
!dma_kmalloc_needs_bounce(dev, size, dir) &&
!range_straddles_page_boundary(phys, size) &&
!xen_arch_need_swiotlb(dev, phys, dev_addr) &&
@@ -253,7 +253,7 @@ static dma_addr_t xen_swiotlb_map_phys(struct device *dev, phys_addr_t phys,
/*
* Ensure that the address returned is DMA'ble
*/
- if (unlikely(!dma_capable(dev, dev_addr, size, true))) {
+ if (unlikely(!dma_capable(dev, dev_addr, size, true, attrs))) {
__swiotlb_tbl_unmap_single(dev, map, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC,
swiotlb_find_pool(dev, map));
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 94fad4e7c11e..daa31a1adf7b 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -135,12 +135,20 @@ static inline bool force_dma_unencrypted(struct device *dev)
#endif /* CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED */
static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
- bool is_ram)
+ bool is_ram, unsigned long attrs)
{
dma_addr_t end = addr + size - 1;
if (addr == DMA_MAPPING_ERROR)
return false;
+ /*
+ * The DMA address was derived from encrypted RAM, but this device
+ * requires unencrypted DMA addresses. Treat it as not DMA-capable
+ * so the caller can fall back to a suitable SWIOTLB pool.
+ */
+ if (!(attrs & DMA_ATTR_CC_SHARED) && force_dma_unencrypted(dev))
+ return false;
+
if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) &&
min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn)))
return false;
diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
index 7140c208c123..e05dc7649366 100644
--- a/kernel/dma/direct.h
+++ b/kernel/dma/direct.h
@@ -101,15 +101,15 @@ static inline dma_addr_t dma_direct_map_phys(struct device *dev,
if (attrs & DMA_ATTR_MMIO) {
dma_addr = phys;
- if (unlikely(!dma_capable(dev, dma_addr, size, false)))
+ if (unlikely(!dma_capable(dev, dma_addr, size, false, attrs)))
goto err_overflow;
} else if (attrs & DMA_ATTR_CC_SHARED) {
dma_addr = phys_to_dma_unencrypted(dev, phys);
- if (unlikely(!dma_capable(dev, dma_addr, size, false)))
+ if (unlikely(!dma_capable(dev, dma_addr, size, false, attrs)))
goto err_overflow;
} else {
dma_addr = phys_to_dma(dev, phys);
- if (unlikely(!dma_capable(dev, dma_addr, size, true)) ||
+ if (unlikely(!dma_capable(dev, dma_addr, size, true, attrs)) ||
dma_kmalloc_needs_bounce(dev, size, dir)) {
if (is_swiotlb_active(dev) &&
!(attrs & DMA_ATTR_REQUIRE_COHERENT))
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 2bf3981db35d..f4e8b241a1c4 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1678,7 +1678,7 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
else
dma_addr = phys_to_dma_encrypted(dev, swiotlb_addr);
- if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
+ if (unlikely(!dma_capable(dev, dma_addr, size, true, attrs))) {
__swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC,
swiotlb_find_pool(dev, swiotlb_addr));
--
2.43.0
^ permalink raw reply related
* [PATCH v6 07/20] dma-mapping: make dma_pgprot() honor DMA_ATTR_CC_SHARED
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Fold encrypted/decrypted pgprot selection into dma_pgprot() so callers
do not need to adjust the page protection separately.
Update dma_pgprot() to apply pgprot_decrypted() when
DMA_ATTR_CC_SHARED is set and pgprot_encrypted() otherwise Convert
the dma-direct allocation and mmap paths to pass DMA_ATTR_CC_SHARED
instead of open-coding force_dma_unencrypted() handling around
dma_pgprot().
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
kernel/dma/direct.c | 8 +++-----
kernel/dma/mapping.c | 16 ++++++++++++----
2 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 0b4a26c6b6fd..e4cba322386d 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -290,9 +290,6 @@ void *dma_direct_alloc(struct device *dev, size_t size,
if (remap) {
pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs);
- if (force_dma_unencrypted(dev))
- prot = pgprot_decrypted(prot);
-
/* remove any dirty cache lines on the kernel alias */
arch_dma_prep_coherent(page, size);
@@ -614,9 +611,10 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long pfn = PHYS_PFN(dma_to_phys(dev, dma_addr));
int ret = -ENXIO;
- vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
if (force_dma_unencrypted(dev))
- vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
+ attrs |= DMA_ATTR_CC_SHARED;
+
+ vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
return ret;
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index e6b07f160d20..3f4ae283c466 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -539,13 +539,21 @@ EXPORT_SYMBOL(dma_get_sgtable_attrs);
*/
pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs)
{
+ pgprot_t dma_prot;
+
if (dev_is_dma_coherent(dev))
- return prot;
+ dma_prot = prot;
#ifdef CONFIG_ARCH_HAS_DMA_WRITE_COMBINE
- if (attrs & DMA_ATTR_WRITE_COMBINE)
- return pgprot_writecombine(prot);
+ else if (attrs & DMA_ATTR_WRITE_COMBINE)
+ dma_prot = pgprot_writecombine(prot);
#endif
- return pgprot_dmacoherent(prot);
+ else
+ dma_prot = pgprot_dmacoherent(prot);
+
+ if (attrs & DMA_ATTR_CC_SHARED)
+ return pgprot_decrypted(dma_prot);
+ else
+ return pgprot_encrypted(dma_prot);
}
#endif /* CONFIG_MMU */
--
2.43.0
^ permalink raw reply related
* [PATCH v6 06/20] dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Teach swiotlb to distinguish between encrypted and decrypted bounce
buffer pools, and make allocation and mapping paths select a pool whose
state matches the requested DMA attributes.
Add a unencrypted flag to io_tlb_mem, initialize it for the default and
restricted pools, and propagate DMA_ATTR_CC_SHARED into swiotlb pool
allocation. Reject swiotlb alloc/map requests when the selected pool does
not match the required encrypted/decrypted state.
Also return DMA addresses with the matching phys_to_dma_{encrypted,
unencrypted} helper so the DMA address encoding stays consistent with the
chosen pool.
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
include/linux/dma-direct.h | 10 +++
include/linux/swiotlb.h | 8 +-
kernel/dma/direct.c | 13 +++-
kernel/dma/swiotlb.c | 154 ++++++++++++++++++++++++++++---------
4 files changed, 142 insertions(+), 43 deletions(-)
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index c249912456f9..94fad4e7c11e 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -77,6 +77,10 @@ static inline dma_addr_t dma_range_map_max(const struct bus_dma_region *map)
#ifndef phys_to_dma_unencrypted
#define phys_to_dma_unencrypted phys_to_dma
#endif
+
+#ifndef phys_to_dma_encrypted
+#define phys_to_dma_encrypted phys_to_dma
+#endif
#else
static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
{
@@ -90,6 +94,12 @@ static inline dma_addr_t phys_to_dma_unencrypted(struct device *dev,
{
return dma_addr_unencrypted(__phys_to_dma(dev, paddr));
}
+
+static inline dma_addr_t phys_to_dma_encrypted(struct device *dev,
+ phys_addr_t paddr)
+{
+ return dma_addr_encrypted(__phys_to_dma(dev, paddr));
+}
/*
* If memory encryption is supported, phys_to_dma will set the memory encryption
* bit in the DMA address, and dma_to_phys will clear it.
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 29187cec90d8..4dcbf3931be1 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -81,6 +81,7 @@ struct io_tlb_pool {
struct list_head node;
struct rcu_head rcu;
bool transient;
+ bool unencrypted;
#endif
};
@@ -111,6 +112,7 @@ struct io_tlb_mem {
struct dentry *debugfs;
bool force_bounce;
bool for_alloc;
+ bool unencrypted;
#ifdef CONFIG_SWIOTLB_DYNAMIC
bool can_grow;
u64 phys_limit;
@@ -282,7 +284,8 @@ static inline void swiotlb_sync_single_for_cpu(struct device *dev,
extern void swiotlb_print_info(void);
#ifdef CONFIG_DMA_RESTRICTED_POOL
-struct page *swiotlb_alloc(struct device *dev, size_t size);
+struct page *swiotlb_alloc(struct device *dev, size_t size,
+ unsigned long attrs);
bool swiotlb_free(struct device *dev, struct page *page, size_t size);
void swiotlb_free_from_pool(struct device *dev, phys_addr_t tlb_addr,
size_t size, struct io_tlb_pool *pool);
@@ -292,7 +295,8 @@ static inline bool is_swiotlb_for_alloc(struct device *dev)
return dev->dma_io_tlb_mem->for_alloc;
}
#else
-static inline struct page *swiotlb_alloc(struct device *dev, size_t size)
+static inline struct page *swiotlb_alloc(struct device *dev, size_t size,
+ unsigned long attrs)
{
return NULL;
}
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 681f16a984ab..0b4a26c6b6fd 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -96,9 +96,10 @@ static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size)
return ret;
}
-static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t size)
+static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t size,
+ unsigned long attrs)
{
- struct page *page = swiotlb_alloc(dev, size);
+ struct page *page = swiotlb_alloc(dev, size, attrs);
if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
swiotlb_free(dev, page, size);
@@ -258,8 +259,12 @@ void *dma_direct_alloc(struct device *dev, size_t size,
gfp, attrs);
if (is_swiotlb_for_alloc(dev)) {
- page = dma_direct_alloc_swiotlb(dev, size);
+ page = dma_direct_alloc_swiotlb(dev, size, attrs);
if (page) {
+ /*
+ * swiotlb allocations comes from pool already marked
+ * decrypted
+ */
mark_mem_decrypt = false;
goto setup_page;
}
@@ -407,7 +412,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
gfp, attrs);
if (is_swiotlb_for_alloc(dev)) {
- page = dma_direct_alloc_swiotlb(dev, size);
+ page = dma_direct_alloc_swiotlb(dev, size, attrs);
if (!page)
return NULL;
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 78ce05857c00..2bf3981db35d 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -259,10 +259,21 @@ void __init swiotlb_update_mem_attributes(void)
struct io_tlb_pool *mem = &io_tlb_default_mem.defpool;
unsigned long bytes;
+ /*
+ * if platform support memory encryption, swiotlb buffers are
+ * decrypted by default.
+ */
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
+ io_tlb_default_mem.unencrypted = true;
+ else
+ io_tlb_default_mem.unencrypted = false;
+
if (!mem->nslabs || mem->late_alloc)
return;
bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
- set_memory_decrypted((unsigned long)mem->vaddr, bytes >> PAGE_SHIFT);
+
+ if (io_tlb_default_mem.unencrypted)
+ set_memory_decrypted((unsigned long)mem->vaddr, bytes >> PAGE_SHIFT);
}
static void swiotlb_init_io_tlb_pool(struct io_tlb_pool *mem, phys_addr_t start,
@@ -505,8 +516,10 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask,
if (!mem->slots)
goto error_slots;
- set_memory_decrypted((unsigned long)vstart,
- (nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT);
+ if (io_tlb_default_mem.unencrypted)
+ set_memory_decrypted((unsigned long)vstart,
+ (nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT);
+
swiotlb_init_io_tlb_pool(mem, virt_to_phys(vstart), nslabs, true,
nareas);
add_mem_pool(&io_tlb_default_mem, mem);
@@ -539,7 +552,9 @@ void __init swiotlb_exit(void)
tbl_size = PAGE_ALIGN(mem->end - mem->start);
slots_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), mem->nslabs));
- set_memory_encrypted(tbl_vaddr, tbl_size >> PAGE_SHIFT);
+ if (io_tlb_default_mem.unencrypted)
+ set_memory_encrypted(tbl_vaddr, tbl_size >> PAGE_SHIFT);
+
if (mem->late_alloc) {
area_order = get_order(array_size(sizeof(*mem->areas),
mem->nareas));
@@ -563,6 +578,7 @@ void __init swiotlb_exit(void)
* @gfp: GFP flags for the allocation.
* @bytes: Size of the buffer.
* @phys_limit: Maximum allowed physical address of the buffer.
+ * @unencrypted: true to allocate unencrypted memory, false for encrypted memory
*
* Allocate pages from the buddy allocator. If successful, make the allocated
* pages decrypted that they can be used for DMA.
@@ -570,7 +586,8 @@ void __init swiotlb_exit(void)
* Return: Decrypted pages, %NULL on allocation failure, or ERR_PTR(-EAGAIN)
* if the allocated physical address was above @phys_limit.
*/
-static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, u64 phys_limit)
+static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes,
+ u64 phys_limit, bool unencrypted)
{
unsigned int order = get_order(bytes);
struct page *page;
@@ -588,13 +605,13 @@ static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, u64 phys_limit)
}
vaddr = phys_to_virt(paddr);
- if (set_memory_decrypted((unsigned long)vaddr, PFN_UP(bytes)))
+ if (unencrypted && set_memory_decrypted((unsigned long)vaddr, PFN_UP(bytes)))
goto error;
return page;
error:
/* Intentional leak if pages cannot be encrypted again. */
- if (!set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes)))
+ if (unencrypted && !set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes)))
__free_pages(page, order);
return NULL;
}
@@ -604,30 +621,26 @@ static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, u64 phys_limit)
* @dev: Device for which a memory pool is allocated.
* @bytes: Size of the buffer.
* @phys_limit: Maximum allowed physical address of the buffer.
+ * @attrs: DMA attributes for the allocation.
* @gfp: GFP flags for the allocation.
*
* Return: Allocated pages, or %NULL on allocation failure.
*/
static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes,
- u64 phys_limit, gfp_t gfp)
+ u64 phys_limit, unsigned long attrs, gfp_t gfp)
{
struct page *page;
- unsigned long attrs = 0;
/*
* Allocate from the atomic pools if memory is encrypted and
* the allocation is atomic, because decrypting may block.
*/
- if (!gfpflags_allow_blocking(gfp) && dev && force_dma_unencrypted(dev)) {
+ if (!gfpflags_allow_blocking(gfp) && (attrs & DMA_ATTR_CC_SHARED)) {
void *vaddr;
if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL))
return NULL;
- /* swiotlb considered decrypted by default */
- if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
- attrs = DMA_ATTR_CC_SHARED;
-
return dma_alloc_from_pool(dev, bytes, &vaddr, gfp,
attrs, dma_coherent_ok);
}
@@ -638,7 +651,8 @@ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes,
else if (phys_limit <= DMA_BIT_MASK(32))
gfp |= __GFP_DMA32;
- while (IS_ERR(page = alloc_dma_pages(gfp, bytes, phys_limit))) {
+ while (IS_ERR(page = alloc_dma_pages(gfp, bytes, phys_limit,
+ !!(attrs & DMA_ATTR_CC_SHARED)))) {
if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
phys_limit < DMA_BIT_MASK(64) &&
!(gfp & (__GFP_DMA32 | __GFP_DMA)))
@@ -657,15 +671,18 @@ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes,
* swiotlb_free_tlb() - free a dynamically allocated IO TLB buffer
* @vaddr: Virtual address of the buffer.
* @bytes: Size of the buffer.
+ * @unencrypted: true if @vaddr was allocated decrypted and must be
+ * re-encrypted before being freed
*/
-static void swiotlb_free_tlb(void *vaddr, size_t bytes)
+static void swiotlb_free_tlb(void *vaddr, size_t bytes, bool unencrypted)
{
if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
dma_free_from_pool(NULL, vaddr, bytes))
return;
/* Intentional leak if pages cannot be encrypted again. */
- if (!set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes)))
+ if (!unencrypted ||
+ !set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes)))
__free_pages(virt_to_page(vaddr), get_order(bytes));
}
@@ -676,6 +693,7 @@ static void swiotlb_free_tlb(void *vaddr, size_t bytes)
* @nslabs: Desired (maximum) number of slabs.
* @nareas: Number of areas.
* @phys_limit: Maximum DMA buffer physical address.
+ * @attrs: DMA attributes for the allocation.
* @gfp: GFP flags for the allocations.
*
* Allocate and initialize a new IO TLB memory pool. The actual number of
@@ -686,7 +704,8 @@ static void swiotlb_free_tlb(void *vaddr, size_t bytes)
*/
static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev,
unsigned long minslabs, unsigned long nslabs,
- unsigned int nareas, u64 phys_limit, gfp_t gfp)
+ unsigned int nareas, u64 phys_limit,
+ unsigned long attrs, gfp_t gfp)
{
struct io_tlb_pool *pool;
unsigned int slot_order;
@@ -704,9 +723,10 @@ static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev,
if (!pool)
goto error;
pool->areas = (void *)pool + sizeof(*pool);
+ pool->unencrypted = !!(attrs & DMA_ATTR_CC_SHARED);
tlb_size = nslabs << IO_TLB_SHIFT;
- while (!(tlb = swiotlb_alloc_tlb(dev, tlb_size, phys_limit, gfp))) {
+ while (!(tlb = swiotlb_alloc_tlb(dev, tlb_size, phys_limit, attrs, gfp))) {
if (nslabs <= minslabs)
goto error_tlb;
nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
@@ -724,7 +744,8 @@ static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev,
return pool;
error_slots:
- swiotlb_free_tlb(page_address(tlb), tlb_size);
+ swiotlb_free_tlb(page_address(tlb), tlb_size,
+ !!(attrs & DMA_ATTR_CC_SHARED));
error_tlb:
kfree(pool);
error:
@@ -742,7 +763,9 @@ static void swiotlb_dyn_alloc(struct work_struct *work)
struct io_tlb_pool *pool;
pool = swiotlb_alloc_pool(NULL, IO_TLB_MIN_SLABS, default_nslabs,
- default_nareas, mem->phys_limit, GFP_KERNEL);
+ default_nareas, mem->phys_limit,
+ mem->unencrypted ? DMA_ATTR_CC_SHARED : 0,
+ GFP_KERNEL);
if (!pool) {
pr_warn_ratelimited("Failed to allocate new pool");
return;
@@ -762,7 +785,7 @@ static void swiotlb_dyn_free(struct rcu_head *rcu)
size_t tlb_size = pool->end - pool->start;
free_pages((unsigned long)pool->slots, get_order(slots_size));
- swiotlb_free_tlb(pool->vaddr, tlb_size);
+ swiotlb_free_tlb(pool->vaddr, tlb_size, pool->unencrypted);
kfree(pool);
}
@@ -1037,13 +1060,11 @@ static void dec_transient_used(struct io_tlb_mem *mem, unsigned int nslots)
* Return: Index of the first allocated slot, or -1 on error.
*/
static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool,
- int area_index, phys_addr_t orig_addr, size_t alloc_size,
- unsigned int alloc_align_mask)
+ int area_index, phys_addr_t orig_addr, dma_addr_t tbl_dma_addr,
+ size_t alloc_size, unsigned int alloc_align_mask)
{
struct io_tlb_area *area = pool->areas + area_index;
unsigned long boundary_mask = dma_get_seg_boundary(dev);
- dma_addr_t tbl_dma_addr =
- phys_to_dma_unencrypted(dev, pool->start) & boundary_mask;
unsigned long max_slots = get_max_slots(boundary_mask);
unsigned int iotlb_align_mask = dma_get_min_align_mask(dev);
unsigned int nslots = nr_slots(alloc_size), stride;
@@ -1056,6 +1077,8 @@ static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool
BUG_ON(!nslots);
BUG_ON(area_index >= pool->nareas);
+ tbl_dma_addr &= boundary_mask;
+
/*
* Historically, swiotlb allocations >= PAGE_SIZE were guaranteed to be
* page-aligned in the absence of any other alignment requirements.
@@ -1167,6 +1190,7 @@ static int swiotlb_search_area(struct device *dev, int start_cpu,
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
+ dma_addr_t tbl_dma_addr;
int area_index;
int index = -1;
@@ -1175,9 +1199,15 @@ static int swiotlb_search_area(struct device *dev, int start_cpu,
if (cpu_offset >= pool->nareas)
continue;
area_index = (start_cpu + cpu_offset) & (pool->nareas - 1);
+
+ if (mem->unencrypted)
+ tbl_dma_addr = phys_to_dma_unencrypted(dev, pool->start);
+ else
+ tbl_dma_addr = phys_to_dma_encrypted(dev, pool->start);
+
index = swiotlb_search_pool_area(dev, pool, area_index,
- orig_addr, alloc_size,
- alloc_align_mask);
+ orig_addr, tbl_dma_addr,
+ alloc_size, alloc_align_mask);
if (index >= 0) {
*retpool = pool;
break;
@@ -1207,6 +1237,7 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
+ dma_addr_t tbl_dma_addr;
unsigned long nslabs;
unsigned long flags;
u64 phys_limit;
@@ -1232,11 +1263,17 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
nslabs = nr_slots(alloc_size);
phys_limit = min_not_zero(*dev->dma_mask, dev->bus_dma_limit);
pool = swiotlb_alloc_pool(dev, nslabs, nslabs, 1, phys_limit,
+ mem->unencrypted ? DMA_ATTR_CC_SHARED : 0,
GFP_NOWAIT);
if (!pool)
return -1;
- index = swiotlb_search_pool_area(dev, pool, 0, orig_addr,
+ if (mem->unencrypted)
+ tbl_dma_addr = phys_to_dma_unencrypted(dev, pool->start);
+ else
+ tbl_dma_addr = phys_to_dma_encrypted(dev, pool->start);
+
+ index = swiotlb_search_pool_area(dev, pool, 0, orig_addr, tbl_dma_addr,
alloc_size, alloc_align_mask);
if (index < 0) {
swiotlb_dyn_free(&pool->rcu);
@@ -1281,15 +1318,23 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
size_t alloc_size, unsigned int alloc_align_mask,
struct io_tlb_pool **retpool)
{
+ struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
+ dma_addr_t tbl_dma_addr;
int start, i;
int index;
- *retpool = pool = &dev->dma_io_tlb_mem->defpool;
+ *retpool = pool = &mem->defpool;
+ if (mem->unencrypted)
+ tbl_dma_addr = phys_to_dma_unencrypted(dev, pool->start);
+ else
+ tbl_dma_addr = phys_to_dma_encrypted(dev, pool->start);
+
i = start = raw_smp_processor_id() & (pool->nareas - 1);
do {
index = swiotlb_search_pool_area(dev, pool, i, orig_addr,
- alloc_size, alloc_align_mask);
+ tbl_dma_addr, alloc_size,
+ alloc_align_mask);
if (index >= 0)
return index;
if (++i >= pool->nareas)
@@ -1372,9 +1417,19 @@ static unsigned long mem_used(struct io_tlb_mem *mem)
* any pre- or post-padding for alignment
* @alloc_align_mask: Required start and end alignment of the allocated buffer
* @dir: DMA direction
- * @attrs: Optional DMA attributes for the map operation
+ * @attrs: Optional DMA attributes for the map operation, updated
+ * to match the selected SWIOTLB pool
*
* Find and allocate a suitable sequence of IO TLB slots for the request.
+ * The device's SWIOTLB pool must match the device's current DMA encryption
+ * requirements. If the device requires decrypted DMA, bouncing is done through
+ * an unencrypted pool and the mapping is marked shared. If the device can DMA
+ * to encrypted memory, bouncing is done through an encrypted pool even when the
+ * original DMA address was unencrypted. Enabling encrypted DMA for a device is
+ * therefore expected to update its default io_tlb_mem to an encrypted pool, so
+ * later bounce mappings for both encrypted and decrypted original memory use
+ * that encrypted pool.
+ *
* The allocated space starts at an alignment specified by alloc_align_mask,
* and the size of the allocated space is rounded up so that the total amount
* of allocated space is a multiple of (alloc_align_mask + 1). If
@@ -1411,6 +1466,16 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
+ /* swiotlb pool is incorrect for this device */
+ if (unlikely(mem->unencrypted != force_dma_unencrypted(dev)))
+ return (phys_addr_t)DMA_MAPPING_ERROR;
+
+ /* Force attrs to match the kind of memory in the pool */
+ if (mem->unencrypted)
+ *attrs |= DMA_ATTR_CC_SHARED;
+ else
+ *attrs &= ~DMA_ATTR_CC_SHARED;
+
/*
* The default swiotlb memory pool is allocated with PAGE_SIZE
* alignment. If a mapping is requested with larger alignment,
@@ -1608,8 +1673,11 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR)
return DMA_MAPPING_ERROR;
- /* Ensure that the address returned is DMA'ble */
- dma_addr = phys_to_dma_unencrypted(dev, swiotlb_addr);
+ if (attrs & DMA_ATTR_CC_SHARED)
+ dma_addr = phys_to_dma_unencrypted(dev, swiotlb_addr);
+ else
+ dma_addr = phys_to_dma_encrypted(dev, swiotlb_addr);
+
if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
__swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC,
@@ -1773,7 +1841,7 @@ static inline void swiotlb_create_debugfs_files(struct io_tlb_mem *mem,
#ifdef CONFIG_DMA_RESTRICTED_POOL
-struct page *swiotlb_alloc(struct device *dev, size_t size)
+struct page *swiotlb_alloc(struct device *dev, size_t size, unsigned long attrs)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
@@ -1784,6 +1852,9 @@ struct page *swiotlb_alloc(struct device *dev, size_t size)
if (!mem)
return NULL;
+ if (mem->unencrypted != !!(attrs & DMA_ATTR_CC_SHARED))
+ return NULL;
+
align = (1 << (get_order(size) + PAGE_SHIFT)) - 1;
index = swiotlb_find_slots(dev, 0, size, align, &pool);
if (index == -1)
@@ -1859,9 +1930,18 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
kfree(mem);
return -ENOMEM;
}
+ /*
+ * if platform supports memory encryption,
+ * restricted mem pool is decrypted by default
+ */
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
+ mem->unencrypted = true;
+ set_memory_decrypted((unsigned long)phys_to_virt(rmem->base),
+ rmem->size >> PAGE_SHIFT);
+ } else {
+ mem->unencrypted = false;
+ }
- set_memory_decrypted((unsigned long)phys_to_virt(rmem->base),
- rmem->size >> PAGE_SHIFT);
swiotlb_init_io_tlb_pool(pool, rmem->base, nslabs,
false, nareas);
mem->force_bounce = true;
--
2.43.0
^ permalink raw reply related
* [PATCH v6 05/20] dma: swiotlb: pass mapping attributes by reference
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Change swiotlb_tbl_map_single() to take the DMA mapping attributes by
reference and update the direct callers accordingly.
This is a preparatory change for a follow-up patch which updates the
attributes based on the selected swiotlb pool. Keeping the signature change
separate makes the follow-up patch easier to review.
No functional change in this patch.
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
drivers/iommu/dma-iommu.c | 2 +-
drivers/xen/swiotlb-xen.c | 2 +-
include/linux/swiotlb.h | 2 +-
kernel/dma/swiotlb.c | 6 +++---
4 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index c2595bee3d41..725c7adb0a8d 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1180,7 +1180,7 @@ static phys_addr_t iommu_dma_map_swiotlb(struct device *dev, phys_addr_t phys,
trace_swiotlb_bounced(dev, phys, size);
phys = swiotlb_tbl_map_single(dev, phys, size, iova_mask(iovad), dir,
- attrs);
+ &attrs);
/*
* Untrusted devices should not see padding areas with random leftover
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 2cbf2b588f5b..8c4abe65cd49 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -243,7 +243,7 @@ static dma_addr_t xen_swiotlb_map_phys(struct device *dev, phys_addr_t phys,
*/
trace_swiotlb_bounced(dev, dev_addr, size);
- map = swiotlb_tbl_map_single(dev, phys, size, 0, dir, attrs);
+ map = swiotlb_tbl_map_single(dev, phys, size, 0, dir, &attrs);
if (map == (phys_addr_t)DMA_MAPPING_ERROR)
return DMA_MAPPING_ERROR;
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 133bb8ca9032..29187cec90d8 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -238,7 +238,7 @@ static inline phys_addr_t default_swiotlb_limit(void)
phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,
size_t mapping_size, unsigned int alloc_aligned_mask,
- enum dma_data_direction dir, unsigned long attrs);
+ enum dma_data_direction dir, unsigned long *attrs);
dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys,
size_t size, enum dma_data_direction dir, unsigned long attrs);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index be4d418d92ac..78ce05857c00 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1391,7 +1391,7 @@ static unsigned long mem_used(struct io_tlb_mem *mem)
*/
phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
size_t mapping_size, unsigned int alloc_align_mask,
- enum dma_data_direction dir, unsigned long attrs)
+ enum dma_data_direction dir, unsigned long *attrs)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
unsigned int offset;
@@ -1425,7 +1425,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
size = ALIGN(mapping_size + offset, alloc_align_mask + 1);
index = swiotlb_find_slots(dev, orig_addr, size, alloc_align_mask, &pool);
if (index == -1) {
- if (!(attrs & DMA_ATTR_NO_WARN))
+ if (!(*attrs & DMA_ATTR_NO_WARN))
dev_warn_ratelimited(dev,
"swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
size, mem->nslabs, mem_used(mem));
@@ -1604,7 +1604,7 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size);
- swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, 0, dir, attrs);
+ swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, 0, dir, &attrs);
if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR)
return DMA_MAPPING_ERROR;
--
2.43.0
^ permalink raw reply related
* [PATCH v6 04/20] dma-pool: track decrypted atomic pools and select them via attrs
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Teach the atomic DMA pool code to distinguish between encrypted and
unencrypted pools, and make pool allocation select the matching pool based
on DMA attributes.
Introduce a dma_gen_pool wrapper that records whether a pool is
unencrypted, initialize that state when the atomic pools are created, and
use it when expanding and resizing the pools. Update dma_alloc_from_pool()
to take attrs and skip pools whose encrypted state does not match
DMA_ATTR_CC_SHARED. Update dma_free_from_pool() accordingly.
Also pass DMA_ATTR_CC_SHARED from the swiotlb atomic allocation path so
decrypted swiotlb allocations are taken from the correct atomic pool.
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
drivers/iommu/dma-iommu.c | 2 +-
include/linux/dma-map-ops.h | 2 +-
kernel/dma/direct.c | 11 ++-
kernel/dma/pool.c | 167 +++++++++++++++++++++++-------------
kernel/dma/swiotlb.c | 7 +-
5 files changed, 123 insertions(+), 66 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 54d96e847f16..c2595bee3d41 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1673,7 +1673,7 @@ void *iommu_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
!gfpflags_allow_blocking(gfp) && !coherent)
page = dma_alloc_from_pool(dev, PAGE_ALIGN(size), &cpu_addr,
- gfp, NULL);
+ gfp, attrs, NULL);
else
cpu_addr = iommu_dma_alloc_pages(dev, size, &page, gfp, attrs);
if (!cpu_addr)
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 6a1832a73cad..696b2c3a2305 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -212,7 +212,7 @@ void *dma_common_pages_remap(struct page **pages, size_t size, pgprot_t prot,
void dma_common_free_remap(void *cpu_addr, size_t size);
struct page *dma_alloc_from_pool(struct device *dev, size_t size,
- void **cpu_addr, gfp_t flags,
+ void **cpu_addr, gfp_t flags, unsigned long attrs,
bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t));
bool dma_free_from_pool(struct device *dev, void *start, size_t size);
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 90dc5057a0c0..681f16a984ab 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -154,7 +154,7 @@ static bool dma_direct_use_pool(struct device *dev, gfp_t gfp)
}
static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
- dma_addr_t *dma_handle, gfp_t gfp)
+ dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
struct page *page;
u64 phys_limit;
@@ -164,7 +164,8 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
return NULL;
gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit);
- page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok);
+ page = dma_alloc_from_pool(dev, size, &ret, gfp, attrs,
+ dma_coherent_ok);
if (!page)
return NULL;
*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
@@ -253,7 +254,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
*/
if ((remap || (attrs & DMA_ATTR_CC_SHARED)) &&
dma_direct_use_pool(dev, gfp))
- return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+ return dma_direct_alloc_from_pool(dev, size, dma_handle,
+ gfp, attrs);
if (is_swiotlb_for_alloc(dev)) {
page = dma_direct_alloc_swiotlb(dev, size);
@@ -401,7 +403,8 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
attrs |= DMA_ATTR_CC_SHARED;
if ((attrs & DMA_ATTR_CC_SHARED) && dma_direct_use_pool(dev, gfp))
- return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+ return dma_direct_alloc_from_pool(dev, size, dma_handle,
+ gfp, attrs);
if (is_swiotlb_for_alloc(dev)) {
page = dma_direct_alloc_swiotlb(dev, size);
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 2b2fbb709242..be78474a6c49 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -12,12 +12,18 @@
#include <linux/set_memory.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
+#include <linux/cc_platform.h>
-static struct gen_pool *atomic_pool_dma __ro_after_init;
+struct dma_gen_pool {
+ bool unencrypted;
+ struct gen_pool *pool;
+};
+
+static struct dma_gen_pool atomic_pool_dma __ro_after_init;
static unsigned long pool_size_dma;
-static struct gen_pool *atomic_pool_dma32 __ro_after_init;
+static struct dma_gen_pool atomic_pool_dma32 __ro_after_init;
static unsigned long pool_size_dma32;
-static struct gen_pool *atomic_pool_kernel __ro_after_init;
+static struct dma_gen_pool atomic_pool_kernel __ro_after_init;
static unsigned long pool_size_kernel;
/* Size can be defined by the coherent_pool command line */
@@ -76,11 +82,12 @@ static bool cma_in_zone(gfp_t gfp)
return true;
}
-static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
+static int atomic_pool_expand(struct dma_gen_pool *dma_pool, size_t pool_size,
gfp_t gfp)
{
unsigned int order;
struct page *page = NULL;
+ bool leak_pages = false;
void *addr;
int ret = -ENOMEM;
@@ -113,12 +120,17 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
* Memory in the atomic DMA pools must be unencrypted, the pools do not
* shrink so no re-encryption occurs in dma_direct_free().
*/
- ret = set_memory_decrypted((unsigned long)page_to_virt(page),
- 1 << order);
- if (ret)
- goto remove_mapping;
- ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
- pool_size, NUMA_NO_NODE);
+ if (dma_pool->unencrypted) {
+ ret = set_memory_decrypted((unsigned long)page_to_virt(page),
+ 1 << order);
+ if (ret) {
+ leak_pages = true;
+ goto remove_mapping;
+ }
+ }
+
+ ret = gen_pool_add_virt(dma_pool->pool, (unsigned long)addr,
+ page_to_phys(page), pool_size, NUMA_NO_NODE);
if (ret)
goto encrypt_mapping;
@@ -126,62 +138,67 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
return 0;
encrypt_mapping:
- ret = set_memory_encrypted((unsigned long)page_to_virt(page),
- 1 << order);
- if (WARN_ON_ONCE(ret)) {
- /* Decrypt succeeded but encrypt failed, purposely leak */
- goto out;
- }
+ if (dma_pool->unencrypted &&
+ set_memory_encrypted((unsigned long)page_to_virt(page), 1 << order))
+ leak_pages = true;
+
remove_mapping:
#ifdef CONFIG_DMA_DIRECT_REMAP
dma_common_free_remap(addr, pool_size);
free_page:
- __free_pages(page, order);
+ if (!leak_pages)
+ __free_pages(page, order);
#endif
out:
return ret;
}
-static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
+static void atomic_pool_resize(struct dma_gen_pool *dma_pool, gfp_t gfp)
{
- if (pool && gen_pool_avail(pool) < atomic_pool_size)
- atomic_pool_expand(pool, gen_pool_size(pool), gfp);
+ if (dma_pool->pool && gen_pool_avail(dma_pool->pool) < atomic_pool_size)
+ atomic_pool_expand(dma_pool, gen_pool_size(dma_pool->pool), gfp);
}
static void atomic_pool_work_fn(struct work_struct *work)
{
if (IS_ENABLED(CONFIG_ZONE_DMA))
- atomic_pool_resize(atomic_pool_dma,
+ atomic_pool_resize(&atomic_pool_dma,
GFP_KERNEL | GFP_DMA);
if (IS_ENABLED(CONFIG_ZONE_DMA32))
- atomic_pool_resize(atomic_pool_dma32,
+ atomic_pool_resize(&atomic_pool_dma32,
GFP_KERNEL | GFP_DMA32);
- atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
+ atomic_pool_resize(&atomic_pool_kernel, GFP_KERNEL);
}
-static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
- gfp_t gfp)
+static __init struct dma_gen_pool *__dma_atomic_pool_init(struct dma_gen_pool *dma_pool,
+ size_t pool_size, gfp_t gfp)
{
- struct gen_pool *pool;
int ret;
- pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
- if (!pool)
+ dma_pool->pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
+ if (!dma_pool->pool)
return NULL;
- gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
+ gen_pool_set_algo(dma_pool->pool, gen_pool_first_fit_order_align, NULL);
+
+ /* if platform is using memory encryption atomic pools are by default decrypted. */
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
+ dma_pool->unencrypted = true;
+ else
+ dma_pool->unencrypted = false;
- ret = atomic_pool_expand(pool, pool_size, gfp);
+ ret = atomic_pool_expand(dma_pool, pool_size, gfp);
if (ret) {
- gen_pool_destroy(pool);
+ gen_pool_destroy(dma_pool->pool);
+ dma_pool->pool = NULL;
pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
pool_size >> 10, &gfp);
return NULL;
}
pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
- gen_pool_size(pool) >> 10, &gfp);
- return pool;
+ gen_pool_size(dma_pool->pool) >> 10, &gfp);
+ return dma_pool;
}
#ifdef CONFIG_ZONE_DMA32
@@ -207,21 +224,22 @@ static int __init dma_atomic_pool_init(void)
/* All memory might be in the DMA zone(s) to begin with */
if (has_managed_zone(ZONE_NORMAL)) {
- atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
- GFP_KERNEL);
- if (!atomic_pool_kernel)
+ __dma_atomic_pool_init(&atomic_pool_kernel, atomic_pool_size, GFP_KERNEL);
+ if (!atomic_pool_kernel.pool)
ret = -ENOMEM;
}
+
if (has_managed_dma()) {
- atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
- GFP_KERNEL | GFP_DMA);
- if (!atomic_pool_dma)
+ __dma_atomic_pool_init(&atomic_pool_dma, atomic_pool_size,
+ GFP_KERNEL | GFP_DMA);
+ if (!atomic_pool_dma.pool)
ret = -ENOMEM;
}
+
if (has_managed_dma32) {
- atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
- GFP_KERNEL | GFP_DMA32);
- if (!atomic_pool_dma32)
+ __dma_atomic_pool_init(&atomic_pool_dma32, atomic_pool_size,
+ GFP_KERNEL | GFP_DMA32);
+ if (!atomic_pool_dma32.pool)
ret = -ENOMEM;
}
@@ -230,19 +248,44 @@ static int __init dma_atomic_pool_init(void)
}
postcore_initcall(dma_atomic_pool_init);
-static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp)
+static inline struct dma_gen_pool *__dma_guess_pool(struct dma_gen_pool *first,
+ struct dma_gen_pool *second, struct dma_gen_pool *third)
{
- if (prev == NULL) {
+ if (first->pool)
+ return first;
+ if (second && second->pool)
+ return second;
+ if (third && third->pool)
+ return third;
+ return NULL;
+}
+
+static inline struct dma_gen_pool *dma_guess_pool(struct dma_gen_pool *prev,
+ gfp_t gfp)
+{
+ if (!prev) {
if (gfp & GFP_DMA)
- return atomic_pool_dma ?: atomic_pool_dma32 ?: atomic_pool_kernel;
+ return __dma_guess_pool(&atomic_pool_dma,
+ &atomic_pool_dma32,
+ &atomic_pool_kernel);
+
if (gfp & GFP_DMA32)
- return atomic_pool_dma32 ?: atomic_pool_dma ?: atomic_pool_kernel;
- return atomic_pool_kernel ?: atomic_pool_dma32 ?: atomic_pool_dma;
+ return __dma_guess_pool(&atomic_pool_dma32,
+ &atomic_pool_dma,
+ &atomic_pool_kernel);
+
+ return __dma_guess_pool(&atomic_pool_kernel,
+ &atomic_pool_dma32,
+ &atomic_pool_dma);
}
- if (prev == atomic_pool_kernel)
- return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma;
- if (prev == atomic_pool_dma32)
- return atomic_pool_dma;
+
+ if (prev == &atomic_pool_kernel)
+ return __dma_guess_pool(&atomic_pool_dma32,
+ &atomic_pool_dma, NULL);
+
+ if (prev == &atomic_pool_dma32)
+ return __dma_guess_pool(&atomic_pool_dma, NULL, NULL);
+
return NULL;
}
@@ -272,16 +315,20 @@ static struct page *__dma_alloc_from_pool(struct device *dev, size_t size,
}
struct page *dma_alloc_from_pool(struct device *dev, size_t size,
- void **cpu_addr, gfp_t gfp,
+ void **cpu_addr, gfp_t gfp, unsigned long attrs,
bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
{
- struct gen_pool *pool = NULL;
+ struct dma_gen_pool *dma_pool = NULL;
struct page *page;
bool pool_found = false;
- while ((pool = dma_guess_pool(pool, gfp))) {
+ while ((dma_pool = dma_guess_pool(dma_pool, gfp))) {
+
+ if (dma_pool->unencrypted != !!(attrs & DMA_ATTR_CC_SHARED))
+ continue;
+
pool_found = true;
- page = __dma_alloc_from_pool(dev, size, pool, cpu_addr,
+ page = __dma_alloc_from_pool(dev, size, dma_pool->pool, cpu_addr,
phys_addr_ok);
if (page)
return page;
@@ -296,12 +343,14 @@ struct page *dma_alloc_from_pool(struct device *dev, size_t size,
bool dma_free_from_pool(struct device *dev, void *start, size_t size)
{
- struct gen_pool *pool = NULL;
+ struct dma_gen_pool *dma_pool = NULL;
+
+ while ((dma_pool = dma_guess_pool(dma_pool, 0))) {
- while ((pool = dma_guess_pool(pool, 0))) {
- if (!gen_pool_has_addr(pool, (unsigned long)start, size))
+ if (!gen_pool_has_addr(dma_pool->pool, (unsigned long)start, size))
continue;
- gen_pool_free(pool, (unsigned long)start, size);
+
+ gen_pool_free(dma_pool->pool, (unsigned long)start, size);
return true;
}
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index ac03a6856c2e..be4d418d92ac 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -612,6 +612,7 @@ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes,
u64 phys_limit, gfp_t gfp)
{
struct page *page;
+ unsigned long attrs = 0;
/*
* Allocate from the atomic pools if memory is encrypted and
@@ -623,8 +624,12 @@ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes,
if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL))
return NULL;
+ /* swiotlb considered decrypted by default */
+ if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
+ attrs = DMA_ATTR_CC_SHARED;
+
return dma_alloc_from_pool(dev, bytes, &vaddr, gfp,
- dma_coherent_ok);
+ attrs, dma_coherent_ok);
}
gfp &= ~GFP_ZONEMASK;
--
2.43.0
^ permalink raw reply related
* [PATCH v6 03/20] dma-direct: use DMA_ATTR_CC_SHARED in alloc/free paths
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Propagate force_dma_unencrypted() into DMA_ATTR_CC_SHARED in the
dma-direct allocation path and use the attribute to drive the related
decisions.
This updates dma_direct_alloc(), dma_direct_free(), and
dma_direct_alloc_pages() to fold the forced unencrypted case into attrs.
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
kernel/dma/direct.c | 53 +++++++++++++++++++++++++++++++++++++--------
1 file changed, 44 insertions(+), 9 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index a741c8a2ee66..90dc5057a0c0 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -193,16 +193,31 @@ void *dma_direct_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
bool remap = false, set_uncached = false;
- bool mark_mem_decrypt = true;
+ bool mark_mem_decrypt = false;
struct page *page;
void *ret;
+ /*
+ * DMA_ATTR_CC_SHARED is not a caller-visible dma_alloc_*()
+ * attribute. The direct allocator uses it internally after it has
+ * decided that the backing pages must be shared/decrypted, so the
+ * rest of the allocation path can consistently select DMA addresses,
+ * choose compatible pools and restore encryption on free.
+ */
+ if (attrs & DMA_ATTR_CC_SHARED)
+ return NULL;
+
+ if (force_dma_unencrypted(dev)) {
+ attrs |= DMA_ATTR_CC_SHARED;
+ mark_mem_decrypt = true;
+ }
+
size = PAGE_ALIGN(size);
if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN;
- if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
- !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev))
+ if (((attrs & (DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_CC_SHARED)) ==
+ DMA_ATTR_NO_KERNEL_MAPPING) && !is_swiotlb_for_alloc(dev))
return dma_direct_alloc_no_mapping(dev, size, dma_handle, gfp);
if (!dev_is_dma_coherent(dev)) {
@@ -236,7 +251,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
* Remapping or decrypting memory may block, allocate the memory from
* the atomic pools instead if we aren't allowed block.
*/
- if ((remap || force_dma_unencrypted(dev)) &&
+ if ((remap || (attrs & DMA_ATTR_CC_SHARED)) &&
dma_direct_use_pool(dev, gfp))
return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
@@ -312,12 +327,24 @@ void dma_direct_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
{
phys_addr_t phys;
- bool mark_mem_encrypted = true;
+ bool mark_mem_encrypted = false;
struct io_tlb_pool *swiotlb_pool;
unsigned int page_order = get_order(size);
- if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
- !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev)) {
+ /* see dma_direct_alloc() for details */
+ WARN_ON(attrs & DMA_ATTR_CC_SHARED);
+
+ /*
+ * if the device had requested for an unencrypted buffer,
+ * convert it to encrypted on free
+ */
+ if (force_dma_unencrypted(dev)) {
+ attrs |= DMA_ATTR_CC_SHARED;
+ mark_mem_encrypted = true;
+ }
+
+ if (((attrs & (DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_CC_SHARED)) ==
+ DMA_ATTR_NO_KERNEL_MAPPING) && !is_swiotlb_for_alloc(dev)) {
/* cpu_addr is a struct page cookie, not a kernel address */
dma_free_contiguous(dev, cpu_addr, size);
return;
@@ -366,10 +393,14 @@ void dma_direct_free(struct device *dev, size_t size,
struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
{
+ unsigned long attrs = 0;
struct page *page;
void *ret;
- if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
+ if (force_dma_unencrypted(dev))
+ attrs |= DMA_ATTR_CC_SHARED;
+
+ if ((attrs & DMA_ATTR_CC_SHARED) && dma_direct_use_pool(dev, gfp))
return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
if (is_swiotlb_for_alloc(dev)) {
@@ -403,7 +434,11 @@ void dma_direct_free_pages(struct device *dev, size_t size,
phys_addr_t phys;
void *vaddr = page_address(page);
struct io_tlb_pool *swiotlb_pool;
- bool mark_mem_encrypted = true;
+ /*
+ * if the device had requested for an unencrypted buffer,
+ * convert it to encrypted on free
+ */
+ bool mark_mem_encrypted = force_dma_unencrypted(dev);
/* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
--
2.43.0
^ permalink raw reply related
* [PATCH v6 02/20] dma-direct: swiotlb: handle swiotlb alloc/free outside __dma_direct_alloc_pages
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Jiri Pirko,
Michael Kelley
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Move swiotlb allocation out of __dma_direct_alloc_pages() and handle it in
dma_direct_alloc() / dma_direct_alloc_pages().
This is needed for follow-up changes that simplify the handling of
memory encryption/decryption based on the DMA attribute flags.
swiotlb backing pages are already mapped decrypted by
swiotlb_update_mem_attributes() and rmem_swiotlb_device_init(), so
dma-direct should not call dma_set_decrypted() on allocation nor
dma_set_encrypted() on free for swiotlb-backed memory.
Update alloc/free paths to detect swiotlb-backed pages and skip
encrypt/decrypt transitions for those paths. Keep the existing highmem
rejection in dma_direct_alloc_pages() for swiotlb allocations.
Only for "restricted-dma-pool", we currently set `for_alloc = true`, while
rmem_swiotlb_device_init() decrypts the whole pool up front. This pool is
typically used together with "shared-dma-pool", where the shared region is
accessed after remap/ioremap and the returned address is suitable for
decrypted memory access. So existing code paths remain valid.
Tested-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
include/linux/swiotlb.h | 6 ++++
kernel/dma/direct.c | 71 ++++++++++++++++++++++++++++++-----------
kernel/dma/swiotlb.c | 6 ++++
3 files changed, 65 insertions(+), 18 deletions(-)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 3dae0f592063..133bb8ca9032 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -284,6 +284,8 @@ extern void swiotlb_print_info(void);
#ifdef CONFIG_DMA_RESTRICTED_POOL
struct page *swiotlb_alloc(struct device *dev, size_t size);
bool swiotlb_free(struct device *dev, struct page *page, size_t size);
+void swiotlb_free_from_pool(struct device *dev, phys_addr_t tlb_addr,
+ size_t size, struct io_tlb_pool *pool);
static inline bool is_swiotlb_for_alloc(struct device *dev)
{
@@ -299,6 +301,10 @@ static inline bool swiotlb_free(struct device *dev, struct page *page,
{
return false;
}
+static inline void swiotlb_free_from_pool(struct device *dev, phys_addr_t tlb_addr,
+ size_t size, struct io_tlb_pool *pool)
+{
+}
static inline bool is_swiotlb_for_alloc(struct device *dev)
{
return false;
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 583c5922bca2..a741c8a2ee66 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -96,14 +96,6 @@ static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size)
return ret;
}
-static void __dma_direct_free_pages(struct device *dev, struct page *page,
- size_t size)
-{
- if (swiotlb_free(dev, page, size))
- return;
- dma_free_contiguous(dev, page, size);
-}
-
static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t size)
{
struct page *page = swiotlb_alloc(dev, size);
@@ -125,9 +117,6 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
WARN_ON_ONCE(!PAGE_ALIGNED(size));
- if (is_swiotlb_for_alloc(dev))
- return dma_direct_alloc_swiotlb(dev, size);
-
gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit);
page = dma_alloc_contiguous(dev, size, gfp);
if (page) {
@@ -204,6 +193,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
bool remap = false, set_uncached = false;
+ bool mark_mem_decrypt = true;
struct page *page;
void *ret;
@@ -250,11 +240,21 @@ void *dma_direct_alloc(struct device *dev, size_t size,
dma_direct_use_pool(dev, gfp))
return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+ if (is_swiotlb_for_alloc(dev)) {
+ page = dma_direct_alloc_swiotlb(dev, size);
+ if (page) {
+ mark_mem_decrypt = false;
+ goto setup_page;
+ }
+ return NULL;
+ }
+
/* we always manually zero the memory once we are done */
page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true);
if (!page)
return NULL;
+setup_page:
/*
* dma_alloc_contiguous can return highmem pages depending on a
* combination the cma= arguments and per-arch setup. These need to be
@@ -281,7 +281,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
goto out_free_pages;
} else {
ret = page_address(page);
- if (dma_set_decrypted(dev, ret, size))
+ if (mark_mem_decrypt && dma_set_decrypted(dev, ret, size))
goto out_leak_pages;
}
@@ -298,10 +298,11 @@ void *dma_direct_alloc(struct device *dev, size_t size,
return ret;
out_encrypt_pages:
- if (dma_set_encrypted(dev, page_address(page), size))
+ if (mark_mem_decrypt && dma_set_encrypted(dev, page_address(page), size))
return NULL;
out_free_pages:
- __dma_direct_free_pages(dev, page, size);
+ if (!swiotlb_free(dev, page, size))
+ dma_free_contiguous(dev, page, size);
return NULL;
out_leak_pages:
return NULL;
@@ -310,6 +311,9 @@ void *dma_direct_alloc(struct device *dev, size_t size,
void dma_direct_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
{
+ phys_addr_t phys;
+ bool mark_mem_encrypted = true;
+ struct io_tlb_pool *swiotlb_pool;
unsigned int page_order = get_order(size);
if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
@@ -338,16 +342,25 @@ void dma_direct_free(struct device *dev, size_t size,
dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size)))
return;
+ phys = dma_to_phys(dev, dma_addr);
+ swiotlb_pool = swiotlb_find_pool(dev, phys);
+ if (swiotlb_pool)
+ /* Swiotlb doesn't need a page attribute update on free */
+ mark_mem_encrypted = false;
+
if (is_vmalloc_addr(cpu_addr)) {
vunmap(cpu_addr);
} else {
if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED))
arch_dma_clear_uncached(cpu_addr, size);
- if (dma_set_encrypted(dev, cpu_addr, size))
+ if (mark_mem_encrypted && dma_set_encrypted(dev, cpu_addr, size))
return;
}
- __dma_direct_free_pages(dev, dma_direct_to_page(dev, dma_addr), size);
+ if (swiotlb_pool)
+ swiotlb_free_from_pool(dev, phys, size, swiotlb_pool);
+ else
+ dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size);
}
struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
@@ -359,6 +372,15 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+ if (is_swiotlb_for_alloc(dev)) {
+ page = dma_direct_alloc_swiotlb(dev, size);
+ if (!page)
+ return NULL;
+
+ ret = page_address(page);
+ goto setup_page;
+ }
+
page = __dma_direct_alloc_pages(dev, size, gfp, false);
if (!page)
return NULL;
@@ -366,6 +388,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
ret = page_address(page);
if (dma_set_decrypted(dev, ret, size))
goto out_leak_pages;
+setup_page:
memset(ret, 0, size);
*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
return page;
@@ -377,16 +400,28 @@ void dma_direct_free_pages(struct device *dev, size_t size,
struct page *page, dma_addr_t dma_addr,
enum dma_data_direction dir)
{
+ phys_addr_t phys;
void *vaddr = page_address(page);
+ struct io_tlb_pool *swiotlb_pool;
+ bool mark_mem_encrypted = true;
/* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
dma_free_from_pool(dev, vaddr, size))
return;
- if (dma_set_encrypted(dev, vaddr, size))
+ phys = page_to_phys(page);
+ swiotlb_pool = swiotlb_find_pool(dev, phys);
+ if (swiotlb_pool)
+ mark_mem_encrypted = false;
+
+ if (mark_mem_encrypted && dma_set_encrypted(dev, vaddr, size))
return;
- __dma_direct_free_pages(dev, page, size);
+
+ if (swiotlb_pool)
+ swiotlb_free_from_pool(dev, phys, size, swiotlb_pool);
+ else
+ dma_free_contiguous(dev, page, size);
}
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 1abd3e6146f4..ac03a6856c2e 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1809,6 +1809,12 @@ bool swiotlb_free(struct device *dev, struct page *page, size_t size)
return true;
}
+void swiotlb_free_from_pool(struct device *dev, phys_addr_t tlb_addr, size_t size,
+ struct io_tlb_pool *pool)
+{
+ swiotlb_release_slots(dev, tlb_addr, pool);
+}
+
static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
struct device *dev)
{
--
2.43.0
^ permalink raw reply related
* [PATCH v6 01/20] s390: Expose protected virtualization through cc_platform_has()
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86, Halil Pasic,
Matthew Rosato, Jaehoon Kim
In-Reply-To: <20260604083959.1265923-1-aneesh.kumar@kernel.org>
Protected virtualization guests use memory encryption, so advertise that to
the rest of the kernel through cc_platform_has(CC_ATTR_MEM_ENCRYPT).
s390 already forces DMA mappings to be unencrypted for protected
virtualization guests through force_dma_unencrypted(). Add
ARCH_HAS_CC_PLATFORM and provide the matching cc_platform_has()
implementation
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
Cc: Halil Pasic <pasic@linux.ibm.com>
Cc: Matthew Rosato <mjrosato@linux.ibm.com>
Cc: Jaehoon Kim <jhkim@linux.ibm.com>
---
arch/s390/Kconfig | 1 +
arch/s390/mm/init.c | 14 ++++++++++++++
2 files changed, 15 insertions(+)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index ecbcbb781e40..9b5e6029e043 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -87,6 +87,7 @@ config S390
select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
select ARCH_HAS_CC_CAN_LINK
+ select ARCH_HAS_CC_PLATFORM
select ARCH_HAS_CPU_FINALIZE_INIT
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DEBUG_VIRTUAL
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 1f72efc2a579..ad3c6d92b801 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -50,6 +50,7 @@
#include <linux/virtio_anchor.h>
#include <linux/virtio_config.h>
#include <linux/execmem.h>
+#include <linux/cc_platform.h>
pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(".bss..swapper_pg_dir");
pgd_t invalid_pg_dir[PTRS_PER_PGD] __section(".bss..invalid_pg_dir");
@@ -140,6 +141,19 @@ bool force_dma_unencrypted(struct device *dev)
return is_prot_virt_guest();
}
+
+bool cc_platform_has(enum cc_attr attr)
+{
+ switch (attr) {
+ case CC_ATTR_MEM_ENCRYPT:
+ return is_prot_virt_guest();
+
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL_GPL(cc_platform_has);
+
/* protected virtualization */
static void __init pv_init(void)
{
--
2.43.0
^ permalink raw reply related
* [PATCH v6 00/20] dma-mapping: Use DMA_ATTR_CC_SHARED through direct, pool and swiotlb paths
From: Aneesh Kumar K.V (Arm) @ 2026-06-04 8:39 UTC (permalink / raw)
To: iommu, linux-arm-kernel, linux-kernel, linux-coco
Cc: Aneesh Kumar K.V (Arm), Robin Murphy, Marek Szyprowski,
Will Deacon, Marc Zyngier, Steven Price, Suzuki K Poulose,
Catalin Marinas, Jiri Pirko, Jason Gunthorpe, Mostafa Saleh,
Petr Tesarik, Alexey Kardashevskiy, Dan Williams, Xu Yilun,
linuxppc-dev, linux-s390, Madhavan Srinivasan, Michael Ellerman,
Nicholas Piggin, Christophe Leroy (CS GROUP), Alexander Gordeev,
Gerald Schaefer, Heiko Carstens, Vasily Gorbik,
Christian Borntraeger, Sven Schnelle, x86
This series propagates DMA_ATTR_CC_SHARED through the dma-direct,
dma-pool, and swiotlb paths so that encrypted and decrypted DMA buffers
are handled consistently.
Today, the direct DMA path mostly relies on force_dma_unencrypted() for
shared/decrypted buffer handling. This series consolidates the
force_dma_unencrypted() checks in the top-level functions and ensures
that the remaining DMA interfaces use DMA attributes to make the correct
decisions.
The series:
- moves swiotlb-backed allocations out of __dma_direct_alloc_pages(),
- propagates DMA_ATTR_CC_SHARED through the dma-direct alloc/free
paths
- teaches the atomic DMA pools to track encrypted versus decrypted
state
- tracks swiotlb pool encryption state and enforces strict pool
selection
- centralizes encrypted/decrypted pgprot handling in dma_pgprot() using
DMA attributes
- passes DMA attributes down to dma_capable() so capability checks can
validate whether the selected DMA address encoding matches
DMA_ATTR_CC_SHARED
- makes dma_direct_map_phys() choose the DMA address encoding from
DMA_ATTR_CC_SHARED and fall back to swiotlb when a shared DMA request
cannot use the direct mapping, which lets arm64 and x86 CCA guests stop
relying on SWIOTLB_FORCE for DMA mappings
- use the selected swiotlb pool state to derive the returned DMA
address.
Changes since v5:
https://lore.kernel.org/all/20260522042815.370873-1-aneesh.kumar@kernel.org
* Add Tested-by
* Drop the pKVM patch, which has now been posted separately:
https://lore.kernel.org/all/20260603110522.3331819-1-smostafa@google.com
* Remove the DO_NOT_MERGE tag from the s390 change.
* Add a patch to drop the SWIOTLB_FORCE flag.
* Rebase onto the latest kernel.
Changes since v4:
https://lore.kernel.org/all/20260512090408.794195-1-aneesh.kumar@kernel.org
* Add new patches based on Sashiko review:
swiotlb: Preserve allocation virtual address for dynamic pools
dma: free atomic pool pages by physical address
dma: swiotlb: handle set_memory_decrypted() failures
dma: swiotlb: free dynamic pools from process context
iommu/dma: Check atomic pool allocation result directly
* Include pKVM and s390 changes as dependent patches. These are not yet
ready to merge and are waiting for subsystem testing feedback.
* Drop the AMD GART patch because it requires wider testing.
* Update swiotlb_tbl_map_single() to take attrs by reference.
* Switch swiotlb_free() to use rcu_work.
* Avoid calling swiotlb_find_pool() multiple times in the free path.
* Make DMA_ATTR_MMIO imply DMA_ATTR_CC_SHARED for devices requiring unencrypted DMA.
Changes from v3:
https://lore.kernel.org/all/20260427055509.898190-1-aneesh.kumar@kernel.org
* Handle DMA_ATTR_MMIO correctly in dma_direct_map_phys()
* Address most of sashiko review
* Rebase to latest kernel
* drop SWIOTLB_FORCE for s390 and powerpc secure guest.
Changes from v2:
https://lore.kernel.org/all/20260420061415.3650870-1-aneesh.kumar@kernel.org
* pass attrs to dma_capable() and update direct, swiotlb, Xen swiotlb, and
x86 GART paths so the capability checks see the DMA address attr value
DMA_ATTR_CC_SHARED.
* rework dma_direct_map_phys() so DMA_ATTR_CC_SHARED selects
phys_to_dma_unencrypted() while the default path uses
phys_to_dma_encrypted(), with swiotlb fallback when the requested
shared/private state cannot be satisfied by a direct DMA address.
* stop relying on SWIOTLB_FORCE for arm64 and x86 CC guest DMA mappings;
swiotlb is still enabled there, but shared mappings is now selected
through the generic dma_direct_map_phys()/dma_capable() decision instead
of a global force-bounce flag.
Changes from v1:
https://lore.kernel.org/all/20260417085900.3062416-1-aneesh.kumar@kernel.org
* rebased to latest kernel (change from DMA_ATTR_CC_DECRYPTED -> DMA_ATTR_CC_SHARED)
* update the alloc path so DMA_ATTR_CC_SHARED is not a caller-visible attribute.
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Mostafa Saleh <smostafa@google.com>
Cc: Petr Tesarik <ptesarik@suse.com>
Cc: Alexey Kardashevskiy <aik@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Xu Yilun <yilun.xu@linux.intel.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: x86@kernel.org
Aneesh Kumar K.V (Arm) (20):
s390: Expose protected virtualization through cc_platform_has()
dma-direct: swiotlb: handle swiotlb alloc/free outside
__dma_direct_alloc_pages
dma-direct: use DMA_ATTR_CC_SHARED in alloc/free paths
dma-pool: track decrypted atomic pools and select them via attrs
dma: swiotlb: pass mapping attributes by reference
dma: swiotlb: track pool encryption state and honor DMA_ATTR_CC_SHARED
dma-mapping: make dma_pgprot() honor DMA_ATTR_CC_SHARED
dma-direct: pass attrs to dma_capable() for DMA_ATTR_CC_SHARED checks
dma-direct: make dma_direct_map_phys() honor DMA_ATTR_CC_SHARED
dma-direct: set decrypted flag for remapped DMA allocations
dma-direct: select DMA address encoding from DMA_ATTR_CC_SHARED
dma-pool: fix page leak in atomic_pool_expand() cleanup
dma-direct: rename ret to cpu_addr in alloc helpers
dma-direct: return struct page from dma_direct_alloc_from_pool()
iommu/dma: Check atomic pool allocation result directly
dma: swiotlb: free dynamic pools from process context
dma: swiotlb: handle set_memory_decrypted() failures
dma: free atomic pool pages by physical address
swiotlb: Preserve allocation virtual address for dynamic pools
swiotlb: remove unused SWIOTLB_FORCE flag
arch/arm64/mm/init.c | 4 +-
arch/powerpc/platforms/pseries/svm.c | 2 +-
arch/s390/Kconfig | 1 +
arch/s390/mm/init.c | 16 +-
arch/x86/kernel/amd_gart_64.c | 30 +--
arch/x86/kernel/pci-dma.c | 4 +-
drivers/iommu/dma-iommu.c | 15 +-
drivers/xen/swiotlb-xen.c | 8 +-
include/linux/dma-direct.h | 20 +-
include/linux/dma-map-ops.h | 3 +-
include/linux/swiotlb.h | 21 +-
kernel/dma/direct.c | 275 +++++++++++++++++++--------
kernel/dma/direct.h | 47 ++---
kernel/dma/mapping.c | 16 +-
kernel/dma/pool.c | 221 +++++++++++++++------
kernel/dma/swiotlb.c | 273 ++++++++++++++++++++------
16 files changed, 692 insertions(+), 264 deletions(-)
base-commit: ba3e43a9e601636f5edb54e259a74f96ca3b8fd8
--
2.43.0
^ permalink raw reply
* Re: [PATCH v7 00/42] guest_memfd: In-place conversion support
From: Ackerley Tng @ 2026-06-03 21:27 UTC (permalink / raw)
To: Ackerley Tng via B4 Relay, aik, andrew.jones, binbin.wu, brauner,
chao.p.peng, david, ira.weiny, jmattson, jthoughton, michael.roth,
oupton, pankaj.gupta, qperret, rick.p.edgecombe, rientjes,
shivankg, steven.price, tabba, willy, wyihan, yan.y.zhao,
forkloop, pratyush, suzuki.poulose, aneesh.kumar, liam,
Paolo Bonzini, Sean Christopherson, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Jonathan Corbet, Shuah Khan,
Shuah Khan, Vishal Annapurve, Andrew Morton, Chris Li,
Kairui Song, Kemeng Shi, Nhat Pham, Baoquan He, Barry Song,
Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park, Qi Zheng,
Shakeel Butt, Kiryl Shutsemau, Jason Gunthorpe, Vlastimil Babka
Cc: kvm, linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest,
linux-mm, linux-coco
In-Reply-To: <20260522-gmem-inplace-conversion-v7-0-2f0fae496530@google.com>
Ackerley Tng via B4 Relay <devnull+ackerleytng.google.com@kernel.org>
writes:
> This is v7 of guest_memfd in-place conversion support.
>
Here's the outstanding items after going over everyone's comments
including Sashiko's:
+ KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION
+ Need to move page clearing into __kvm_gmem_get_pfn to resolve
leak where populate can put initialized kernel memory into TDX
guest
+ See suggested fix at [1]
+ KVM: guest_memfd: Only prepare folios for private pages,
+ s/non-CoCo/CoCo in commit message "INIT_SHARED is about to be
supported for non-CoCo VMs in a later patch in this series
+ Use Suggested-by: Michael Roth <michael.roth@amd.com>
+ KVM: selftests: Test that shared/private status is consistent across
processes
+ Improve test reliability using pthread_mutex
+ I have a fixup patch offline.
I would like feedback on these:
+ KVM: selftests: Test conversion with elevated page refcount
+ Askar pointed out that soon vmsplice may not pin pages. Should I
pin pages through CONFIG_GUP_TEST like in [2]? I prefer not to
take a dependency on CONFIG_GUP_TEST.
+ KVM: selftests: Add script to exercise private_mem_conversions_test
+ Would like to know what people think of a wrapper script before
I address Sashiko's comments.
[1] https://lore.kernel.org/all/CAEvNRgEVC=fFuKVgZYvWyZD7t_zvUZihFG8hrACjvtkD5cwugw@mail.gmail.com/
[2] https://lore.kernel.org/all/baa8838f623102931e755cf34c86314b305af49c.1747264138.git.ackerleytng@google.com/
>
> [...snip...]
>
^ permalink raw reply
* Re: [PATCH v6 1/4] firmware: smccc: Add an Arm SMCCC bus
From: Sudeep Holla @ 2026-06-03 18:52 UTC (permalink / raw)
To: Aneesh Kumar K.V (Arm)
Cc: linux-coco, linux-arm-kernel, linux-kernel, Catalin Marinas,
Greg KH, Jeremy Linton, Jonathan Cameron, Lorenzo Pieralisi,
Mark Rutland, Will Deacon, Steven Price, Suzuki K Poulose
In-Reply-To: <20260527100233.428018-2-aneesh.kumar@kernel.org>
On Wed, May 27, 2026 at 03:32:30PM +0530, Aneesh Kumar K.V (Arm) wrote:
> SMCCC-discovered firmware services are currently represented by separate
> platform devices, such as smccc_trng and arm-cca-dev. Those devices do not
> represent independent DT/ACPI-described platform resources; they are
> features of the SMCCC firmware interface.
>
> Add an Arm SMCCC bus for services discovered through the SMCCC firmware
> interface. The bus provides SMCCC device and driver registration helpers,
> name-based matching, modalias generation, and a sysfs modalias attribute so
> SMCCC service drivers can bind to discovered firmware services and autoload
> as modules.
>
> Follow-up changes can then register SMCCC firmware services as arm-smccc
> devices instead of creating independent per-feature platform devices.
>
This looks good to me.
> Based on arm_ffa code
>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
> ---
> drivers/firmware/smccc/smccc.c | 158 ++++++++++++++++++++++++++++++
I think it is better to keep it separate say bus.c ?
--
Regards,
Sudeep
^ permalink raw reply
* Re: SVSM Development Call June 3rd, 2026
From: Jörg Rödel @ 2026-06-03 18:03 UTC (permalink / raw)
To: coconut-svsm, linux-coco
In-Reply-To: <ah7_t33cbOVFJcbo@8bytes.org>
Meeting minutes are now ready for review:
https://github.com/coconut-svsm/governance/pull/110
-Joerg
^ permalink raw reply
* Re: [PATCH v14 08/44] arm64: RMI: Ensure that the RMM has GPT entries for memory
From: Steven Price @ 2026-06-03 15:48 UTC (permalink / raw)
To: Suzuki K Poulose, Marc Zyngier
Cc: kvm, kvmarm, Catalin Marinas, Will Deacon, James Morse,
Oliver Upton, Zenghui Yu, linux-arm-kernel, linux-kernel,
Joey Gouly, Alexandru Elisei, Christoffer Dall, Fuad Tabba,
linux-coco, Ganapatrao Kulkarni, Gavin Shan, Shanker Donthineni,
Alper Gun, Aneesh Kumar K . V, Emi Kisanuki, Vishal Annapurve,
WeiLin.Chang, Lorenzo.Pieralisi2
In-Reply-To: <e175cb7b-b4fa-4139-b46d-1986e2372d16@arm.com>
On 21/05/2026 16:39, Suzuki K Poulose wrote:
> On 21/05/2026 14:47, Marc Zyngier wrote:
>> On Wed, 13 May 2026 14:17:16 +0100,
>> Steven Price <steven.price@arm.com> wrote:
>>>
>>> The RMM maintains the state of all the granules in the system to make
>>> sure that the host is abiding by the rules. This state can be maintained
>>> at different granularity, per page (TRACKING_FINE) or per region
>>> (TRACKING_COARSE). The region size depends on the underlying
>>> "RMI_GRANULE_SIZE". For a "coarse" region all pages in the region must
>>> be of the same state, this implies we need to have "fine" tracking for
>>> DRAM, so that we can delegated individual pages.
>>>
>>> For now we only support a statically carved out memory for tracking
>>> granules for the "fine" regions. This can be extended in the future to
>>> allow modifying the tracking granularity and remove the need for a
>>> static allocation.
>>>
>>> Similarly, the firmware may create L0 GPT entries describing the total
>>> address space. But if we change the "PAS" (Physical Address Space) of a
>>> granule then the firmware may need to create L1 tables to track the PAS
>>> at a finer granularity.
>>>
>>> Note: support is currently missing for SROs which means that if the RMM
>>> needs memory donating this will fail (and render CCA unusable in Linux).
>>> This effectively means that the L1 GPT tables must be created before
>>> Linux starts.
>>>
>>> Signed-off-by: Steven Price <steven.price@arm.com>
>>> ---
>>> Changes since v13:
>>> * Moved out of KVM
>>> ---
>>> arch/arm64/include/asm/rmi_cmds.h | 2 +
>>> arch/arm64/kernel/rmi.c | 103 ++++++++++++++++++++++++++++++
>>> 2 files changed, 105 insertions(+)
>>>
>>> diff --git a/arch/arm64/include/asm/rmi_cmds.h b/arch/arm64/include/
>>> asm/rmi_cmds.h
>>> index 9179934925c5..9078a2920a7c 100644
>>> --- a/arch/arm64/include/asm/rmi_cmds.h
>>> +++ b/arch/arm64/include/asm/rmi_cmds.h
>>> @@ -33,6 +33,8 @@ struct rmi_sro_state {
>>> } while (RMI_RETURN_STATUS(res.a0) == RMI_BUSY || \
>>> RMI_RETURN_STATUS(res.a0) == RMI_BLOCKED)
>>> +bool rmi_is_available(void);
>>> +
>>> unsigned long rmi_sro_execute(struct rmi_sro_state *sro, gfp_t gfp);
>>> void rmi_sro_free(struct rmi_sro_state *sro);
>>> diff --git a/arch/arm64/kernel/rmi.c b/arch/arm64/kernel/rmi.c
>>> index a14ead5dedda..52a415e99500 100644
>>> --- a/arch/arm64/kernel/rmi.c
>>> +++ b/arch/arm64/kernel/rmi.c
>>> @@ -7,6 +7,8 @@
>>> #include <asm/rmi_cmds.h>
>>> +static bool arm64_rmi_is_available;
>>> +
>>> unsigned long rmm_feat_reg0;
>>> unsigned long rmm_feat_reg1;
>>> @@ -88,6 +90,102 @@ static int rmi_configure(void)
>>> return 0;
>>> }
>>> +/*
>>> + * For now we set the tracking_region_size to 0 for
>>> RMI_RMM_CONFIG_SET().
>>> + * TODO: Support other tracking sizes (via Kconfig option).
>>> + */
>>> +#ifdef CONFIG_PAGE_SIZE_4KB
>>> +#define RMM_GRANULE_TRACKING_SIZE SZ_1G
>>> +#elif defined(CONFIG_PAGE_SIZE_16KB)
>>> +#define RMM_GRANULE_TRACKING_SIZE SZ_32M
>>> +#elif defined(CONFIG_PAGE_SIZE_64KB)
>>> +#define RMM_GRANULE_TRACKING_SIZE SZ_512M
>>> +#endif
>>
>> Basically, a level 2 mapping. Which means this whole block really is:
>>
>> #define RMM_GRANULE_TRAKING_SIZE (2 * PAGE_SHIFT - 3)
>>
>> (adjust for D128 as needed).
>
> True,
As Gavin pointed out we actually don't need this anymore because of the
move to a range based API.
It's also not quite that simple because for 4K PAGE_SIZED the RMM
doesn't support 2MB (which would be the level 2 size), instead jumping
to 1GB. And if we add a Kconfig option in the future then this could
change because of that.
For now I'll just delete this block since it's unused.
>>
>>> +
>>> +/*
>>> + * Make sure the area is tracked by RMM at FINE granularity.
>>> + * We do not support changing the tracking yet.
>>> + */
>>> +static int rmi_verify_memory_tracking(phys_addr_t start, phys_addr_t
>>> end)
>>> +{
>>> + while (start < end) {
>>> + unsigned long ret, category, state, next;
>>> +
>>> + ret = rmi_granule_tracking_get(start, end, &category,
>>> &state, &next);
>>> + if (ret != RMI_SUCCESS ||
>>> + state != RMI_TRACKING_FINE ||
>>> + category != RMI_MEM_CATEGORY_CONVENTIONAL) {
>>> + /* TODO: Set granule tracking in this case */
>>> + pr_err("Granule tracking for region isn't fine/
>>> conventional: %llx",
>>> + start);
>>> + return -ENODEV;
>>
>> How is this triggered? Do we really need to spam the console with
>> this? A PA doesn't mean much, and there is no context (stack trace).
I'm not sure 1 message really counts as 'spam' - it provides the
information on why the RMI interface (and therefore realm guests) is
unavailable. The PA might help track down whether this physical region
was intended to be given to Linux.
> This could be triggered if the RMM doesn't have static carveout
> for tracking the DRAM granules. (state != RMI_TRACKING_FINE).
> This not worth WARN_ONCE(), we could simply not enable KVM.
> We plan to add support for donating memory to the RMM in
> the future. (Primarily we don't yet have an RMM implementation
> that does dynamic management via SRO. This can be added later
> as a separate series)
As Suzuki says - this case should be handled in the future - so it's a
limitation in the current implementation. So a WARN_ONCE is a bit strong
- it's not a "can never happen" situation - it's a "Linux doesn't
support this (yet)".
>>
>> If that's not expected, turn this into a WARN_ONCE().
>
>
>
>
>>
>>> + }
>>> + start = next;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static unsigned long rmi_l0gpt_size(void)
>>> +{
>>> + return 1UL << (30 + FIELD_GET(RMI_FEATURE_REGISTER_1_L0GPTSZ,
>>> + rmm_feat_reg1));
>>> +}
>>> +
>>> +static int rmi_create_gpts(phys_addr_t start, phys_addr_t end)
>>> +{
>>> + unsigned long l0gpt_sz = rmi_l0gpt_size();
>>> +
>>> + start = ALIGN_DOWN(start, l0gpt_sz);
>>> + end = ALIGN(end, l0gpt_sz);
>>> +
>>> + while (start < end) {
>>> + int ret = rmi_gpt_l1_create(start);
>>> +
>>> + /*
>>> + * Make sure the L1 GPT tables are created for the region.
>>> + * RMI_ERROR_GPT indicates the L1 table already exists.
>>> + */
>>> + if (ret && ret != RMI_ERROR_GPT) {
>>> + /*
>>> + * FIXME: Handle SRO so that memory can be donated for
>>> + * the tables.
>>> + */
>>> + pr_err("GPT Level1 table missing for %llx\n", start);
>>> + return -ENOMEM;
>>
>> If any of this fails, where is the cleanup done? Is that part of the
>> missing SRO support that's indicated in the commit message?
>>
>
> For now, there is no cleanup required. What we essentially do here is
> making sure that the GPT tables have been created upto L1 (i.e.,
> by checking ret == RMI_ERROR_GPT).
>
> We do not donate any memory now, but only support RMMs with static
> memory carved out for L1 GPT. Support for dynamic RMMs could be added as
> a separate series, at which point, we could defer the table creation to
> the actual use case (e.g, RMI_GRANULE_DELEGATE).
>
> Clean up would be required when we donate memory to the RMM.
The missing SRO support is why we're not donating memory - with that
missing the clean up is unnecessary as Suzuki says.
>>> + }
>>> + start += l0gpt_sz;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int rmi_init_metadata(void)
>>> +{
>>> + phys_addr_t start, end;
>>> + const struct memblock_region *r;
>>> +
>>> + for_each_mem_region(r) {
>>> + int ret;
>>> +
>>> + start = memblock_region_memory_base_pfn(r) << PAGE_SHIFT;
>>> + end = memblock_region_memory_end_pfn(r) << PAGE_SHIFT;
>>> + ret = rmi_verify_memory_tracking(start, end);
>>> + if (ret)
>>> + return ret;
>>> + ret = rmi_create_gpts(start, end);
>>> + if (ret)
>>> + return ret;
>>> + }
>>
>> How does this work with, say, memory hotplug?
>
> Good point, we need a hook for hotpug to make sure this is taken care
> of. As mentioned above, when we add support for RMM with support for
> dynamic Tracking/GPT with SRO, this could be deferred to the actual
> use (handling RMI return codes, RMI_ERROR_TRACKING/RMI_ERROR_GPT)
Yep, that was an oversight - we definitely will need to handle hotplug.
Thanks,
Steve
> Suzuki
>
>
>>
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +bool rmi_is_available(void)
>>> +{
>>> + return arm64_rmi_is_available;
>>> +}
>>> +
>>> static int __init arm64_init_rmi(void)
>>> {
>>> /* Continue without realm support if we can't agree on a
>>> version */
>>> @@ -101,6 +199,11 @@ static int __init arm64_init_rmi(void)
>>> if (rmi_configure())
>>> return 0;
>>> + if (rmi_init_metadata())
>>> + return 0;
>>> +
>>> + arm64_rmi_is_available = true;
>>> + pr_info("RMI configured");
>>> return 0;
>>> }
>>
>> Thanks,
>>
>> M.
>>
>
^ permalink raw reply
* Re: [PATCH v14 08/44] arm64: RMI: Ensure that the RMM has GPT entries for memory
From: Steven Price @ 2026-06-03 15:48 UTC (permalink / raw)
To: Gavin Shan, kvm, kvmarm
Cc: Catalin Marinas, Marc Zyngier, Will Deacon, James Morse,
Oliver Upton, Suzuki K Poulose, Zenghui Yu, linux-arm-kernel,
linux-kernel, Joey Gouly, Alexandru Elisei, Christoffer Dall,
Fuad Tabba, linux-coco, Ganapatrao Kulkarni, Shanker Donthineni,
Alper Gun, Aneesh Kumar K . V, Emi Kisanuki, Vishal Annapurve,
WeiLin.Chang, Lorenzo.Pieralisi2
In-Reply-To: <2ad282da-88fd-49ab-8145-964ff298ca83@redhat.com>
On 21/05/2026 01:58, Gavin Shan wrote:
> Hi Steven,
>
> On 5/13/26 11:17 PM, Steven Price wrote:
>> The RMM maintains the state of all the granules in the system to make
>> sure that the host is abiding by the rules. This state can be maintained
>> at different granularity, per page (TRACKING_FINE) or per region
>> (TRACKING_COARSE). The region size depends on the underlying
>> "RMI_GRANULE_SIZE". For a "coarse" region all pages in the region must
>> be of the same state, this implies we need to have "fine" tracking for
>> DRAM, so that we can delegated individual pages.
>>
>> For now we only support a statically carved out memory for tracking
>> granules for the "fine" regions. This can be extended in the future to
>> allow modifying the tracking granularity and remove the need for a
>> static allocation.
>>
>> Similarly, the firmware may create L0 GPT entries describing the total
>> address space. But if we change the "PAS" (Physical Address Space) of a
>> granule then the firmware may need to create L1 tables to track the PAS
>> at a finer granularity.
>>
>> Note: support is currently missing for SROs which means that if the RMM
>> needs memory donating this will fail (and render CCA unusable in Linux).
>> This effectively means that the L1 GPT tables must be created before
>> Linux starts.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v13:
>> * Moved out of KVM
>> ---
>> arch/arm64/include/asm/rmi_cmds.h | 2 +
>> arch/arm64/kernel/rmi.c | 103 ++++++++++++++++++++++++++++++
>> 2 files changed, 105 insertions(+)
>>
>> diff --git a/arch/arm64/include/asm/rmi_cmds.h b/arch/arm64/include/
>> asm/rmi_cmds.h
>> index 9179934925c5..9078a2920a7c 100644
>> --- a/arch/arm64/include/asm/rmi_cmds.h
>> +++ b/arch/arm64/include/asm/rmi_cmds.h
>> @@ -33,6 +33,8 @@ struct rmi_sro_state {
>> } while (RMI_RETURN_STATUS(res.a0) == RMI_BUSY || \
>> RMI_RETURN_STATUS(res.a0) == RMI_BLOCKED)
>> +bool rmi_is_available(void);
>> +
>> unsigned long rmi_sro_execute(struct rmi_sro_state *sro, gfp_t gfp);
>> void rmi_sro_free(struct rmi_sro_state *sro);
>> diff --git a/arch/arm64/kernel/rmi.c b/arch/arm64/kernel/rmi.c
>> index a14ead5dedda..52a415e99500 100644
>> --- a/arch/arm64/kernel/rmi.c
>> +++ b/arch/arm64/kernel/rmi.c
>> @@ -7,6 +7,8 @@
>> #include <asm/rmi_cmds.h>
>> +static bool arm64_rmi_is_available;
>> +
>> unsigned long rmm_feat_reg0;
>> unsigned long rmm_feat_reg1;
>> @@ -88,6 +90,102 @@ static int rmi_configure(void)
>> return 0;
>> }
>> +/*
>> + * For now we set the tracking_region_size to 0 for
>> RMI_RMM_CONFIG_SET().
>> + * TODO: Support other tracking sizes (via Kconfig option).
>> + */
>> +#ifdef CONFIG_PAGE_SIZE_4KB
>> +#define RMM_GRANULE_TRACKING_SIZE SZ_1G
>> +#elif defined(CONFIG_PAGE_SIZE_16KB)
>> +#define RMM_GRANULE_TRACKING_SIZE SZ_32M
>> +#elif defined(CONFIG_PAGE_SIZE_64KB)
>> +#define RMM_GRANULE_TRACKING_SIZE SZ_512M
>> +#endif
>> +
>
> RMM_GRANULE_TRACKING_SIZE is never used in this series.
Ah, good spot. In a previous version the tracking size was necessary
when walking below. But the spec was updated to a range based API so
this is no longer necessary.
>> +/*
>> + * Make sure the area is tracked by RMM at FINE granularity.
>> + * We do not support changing the tracking yet.
>> + */
>> +static int rmi_verify_memory_tracking(phys_addr_t start, phys_addr_t
>> end)
>> +{
>> + while (start < end) {
>> + unsigned long ret, category, state, next;
>> +
>> + ret = rmi_granule_tracking_get(start, end, &category, &state,
>> &next);
>> + if (ret != RMI_SUCCESS ||
>> + state != RMI_TRACKING_FINE ||
>> + category != RMI_MEM_CATEGORY_CONVENTIONAL) {
>> + /* TODO: Set granule tracking in this case */
>> + pr_err("Granule tracking for region isn't fine/
>> conventional: %llx",
>> + start);
>> + return -ENODEV;
>> + }
>> + start = next;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static unsigned long rmi_l0gpt_size(void)
>> +{
>> + return 1UL << (30 + FIELD_GET(RMI_FEATURE_REGISTER_1_L0GPTSZ,
>> + rmm_feat_reg1));
>> +}
>> +
>
> rmi_l0gpt_size() is only used by rmi_create_gpts(), its logic can be
> combined to that function.
True - I think partly due to the long line I split this into a separate
function. But I could do something like:
unsigned long l0gpt_sz;
l0gpt_sz = 1UL << (30 + FIELD_GET(RMI_FEATURE_REGISTER_1_L0GPTSZ,
rmi_feat_reg(1)));
which isn't too bad.
Thanks,
Steve
>> +static int rmi_create_gpts(phys_addr_t start, phys_addr_t end)
>> +{
>> + unsigned long l0gpt_sz = rmi_l0gpt_size();
>> +
>> + start = ALIGN_DOWN(start, l0gpt_sz);
>> + end = ALIGN(end, l0gpt_sz);
>> +
>> + while (start < end) {
>> + int ret = rmi_gpt_l1_create(start);
>> +
>> + /*
>> + * Make sure the L1 GPT tables are created for the region.
>> + * RMI_ERROR_GPT indicates the L1 table already exists.
>> + */
>> + if (ret && ret != RMI_ERROR_GPT) {
>> + /*
>> + * FIXME: Handle SRO so that memory can be donated for
>> + * the tables.
>> + */
>> + pr_err("GPT Level1 table missing for %llx\n", start);
>> + return -ENOMEM;
>> + }
>> + start += l0gpt_sz;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int rmi_init_metadata(void)
>> +{
>> + phys_addr_t start, end;
>> + const struct memblock_region *r;
>> +
>> + for_each_mem_region(r) {
>> + int ret;
>> +
>> + start = memblock_region_memory_base_pfn(r) << PAGE_SHIFT;
>> + end = memblock_region_memory_end_pfn(r) << PAGE_SHIFT;
>> + ret = rmi_verify_memory_tracking(start, end);
>> + if (ret)
>> + return ret;
>> + ret = rmi_create_gpts(start, end);
>> + if (ret)
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +bool rmi_is_available(void)
>> +{
>> + return arm64_rmi_is_available;
>> +}
>> +
>> static int __init arm64_init_rmi(void)
>> {
>> /* Continue without realm support if we can't agree on a version */
>> @@ -101,6 +199,11 @@ static int __init arm64_init_rmi(void)
>> if (rmi_configure())
>> return 0;
>> + if (rmi_init_metadata())
>> + return 0;
>> +
>> + arm64_rmi_is_available = true;
>> + pr_info("RMI configured");
>> return 0;
>> }
>
> Thanks,
> Gavin
>
^ permalink raw reply
* Re: [PATCH v14 08/44] arm64: RMI: Ensure that the RMM has GPT entries for memory
From: Steven Price @ 2026-06-03 15:48 UTC (permalink / raw)
To: Aneesh Kumar K.V, kvm, kvmarm
Cc: Catalin Marinas, Marc Zyngier, Will Deacon, James Morse,
Oliver Upton, Suzuki K Poulose, Zenghui Yu, linux-arm-kernel,
linux-kernel, Joey Gouly, Alexandru Elisei, Christoffer Dall,
Fuad Tabba, linux-coco, Ganapatrao Kulkarni, Gavin Shan,
Shanker Donthineni, Alper Gun, Emi Kisanuki, Vishal Annapurve,
WeiLin.Chang, Lorenzo.Pieralisi2
In-Reply-To: <yq5aa4twt03b.fsf@kernel.org>
On 19/05/2026 06:55, Aneesh Kumar K.V wrote:
>> +
>> +bool rmi_is_available(void)
>> +{
>> + return arm64_rmi_is_available;
>> +}
>> +
>
> Can we rename to is_rmi_available(void) ?
Sure, will do.
Thanks,
Steve
^ permalink raw reply
* Re: [PATCH v14 07/44] arm64: RMI: Configure the RMM with the host's page size
From: Steven Price @ 2026-06-03 15:48 UTC (permalink / raw)
To: Marc Zyngier
Cc: kvm, kvmarm, Catalin Marinas, Will Deacon, James Morse,
Oliver Upton, Suzuki K Poulose, Zenghui Yu, linux-arm-kernel,
linux-kernel, Joey Gouly, Alexandru Elisei, Christoffer Dall,
Fuad Tabba, linux-coco, Ganapatrao Kulkarni, Gavin Shan,
Shanker Donthineni, Alper Gun, Aneesh Kumar K . V, Emi Kisanuki,
Vishal Annapurve, WeiLin.Chang, Lorenzo.Pieralisi2
In-Reply-To: <86a4tsx536.wl-maz@kernel.org>
On 21/05/2026 14:30, Marc Zyngier wrote:
> On Wed, 13 May 2026 14:17:15 +0100,
> Steven Price <steven.price@arm.com> wrote:
>>
>> RMM v2.0 brings the ability to set the RMM's granule size. Check the
>> feature registers and configure the RMM so that it matches the host's
>> page size. This means that operations can be done with a granulatity
>> equal to PAGE_SIZE.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v13:
>> * Moved out of KVM.
>> ---
>> arch/arm64/kernel/rmi.c | 42 +++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 42 insertions(+)
>>
>> diff --git a/arch/arm64/kernel/rmi.c b/arch/arm64/kernel/rmi.c
>> index 99c1ccc35c11..a14ead5dedda 100644
>> --- a/arch/arm64/kernel/rmi.c
>> +++ b/arch/arm64/kernel/rmi.c
>> @@ -49,6 +49,45 @@ static int rmi_check_version(void)
>> return 0;
>> }
>>
>> +static int rmi_configure(void)
>> +{
>> + struct rmm_config *config __free(free_page) = NULL;
>> + unsigned long ret;
>> +
>> + config = (struct rmm_config *)get_zeroed_page(GFP_KERNEL);
>> + if (!config)
>> + return -ENOMEM;
>
> This is the sort of buggy construct that is highlighted in
> include/linux/cleanup.h: initialising the object for cleanup with
> NULL, and only later assigning the expected value.
>
> It may not matter here, but it will catch you (or more probably me) in
> the future.
Good spot. I have to admit I'm still getting the hang of these cleanup
handlers.
>> +
>> + switch (PAGE_SIZE) {
>> + case SZ_4K:
>> + config->rmi_granule_size = RMI_GRANULE_SIZE_4KB;
>> + break;
>> + case SZ_16K:
>> + config->rmi_granule_size = RMI_GRANULE_SIZE_16KB;
>> + break;
>> + case SZ_64K:
>> + config->rmi_granule_size = RMI_GRANULE_SIZE_64KB;
>> + break;
>> + default:
>> + pr_err("Unsupported PAGE_SIZE for RMM\n");
>
> Do you really anticipate PAGE_SIZE being any other value? This is 100%
> dead code. If you want to be extra cautious, have a BUILD_BUg_ON().
No, but falling through is clearly wrong (and likely to trigger AI
review comments if nothing else) - BUILD_BUG() sounds like a good solution.
>> + return -EINVAL;
>> + }
>> +
>> + ret = rmi_rmm_config_set(virt_to_phys(config));
>> + if (ret) {
>> + pr_err("RMM config set failed\n");
>> + return -EINVAL;
>> + }
>
> What is the live cycle of the page when the call succeeds? Is it
> switched back to the NS PAS and allowed to be freed?
Yes, as Suzuki answered - it never leaves the NS PAS. The RMM just reads it.
Thanks,
Steve
>> +
>> + ret = rmi_rmm_activate();
>> + if (ret) {
>> + pr_err("RMM activate failed\n");
>> + return -ENXIO;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static int __init arm64_init_rmi(void)
>> {
>> /* Continue without realm support if we can't agree on a version */
>> @@ -60,6 +99,9 @@ static int __init arm64_init_rmi(void)
>> if (WARN_ON(rmi_features(1, &rmm_feat_reg1)))
>> return 0;
>>
>> + if (rmi_configure())
>> + return 0;
>> +
>> return 0;
>> }
>> subsys_initcall(arm64_init_rmi);
>
> Thanks,
>
> M.
>
^ permalink raw reply
* Re: [PATCH v7 07/42] KVM: guest_memfd: Only prepare folios for private pages
From: Michael Roth @ 2026-06-03 13:54 UTC (permalink / raw)
To: Ackerley Tng
Cc: Suzuki K Poulose, aik, andrew.jones, binbin.wu, brauner,
chao.p.peng, david, ira.weiny, jmattson, jthoughton, oupton,
pankaj.gupta, qperret, rick.p.edgecombe, rientjes, shivankg,
steven.price, tabba, willy, wyihan, yan.y.zhao, forkloop,
pratyush, aneesh.kumar, liam, Paolo Bonzini, Sean Christopherson,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Steven Rostedt, Masami Hiramatsu,
Mathieu Desnoyers, Jonathan Corbet, Shuah Khan, Shuah Khan,
Vishal Annapurve, Andrew Morton, Chris Li, Kairui Song,
Kemeng Shi, Nhat Pham, Baoquan He, Barry Song, Axel Rasmussen,
Yuanchu Xie, Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt,
Kiryl Shutsemau, Jason Gunthorpe, Vlastimil Babka, kvm,
linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest,
linux-mm, linux-coco
In-Reply-To: <CAEvNRgGzOnA34WyOHtkOx5MZDZhOHaXAe+nD75AiJsZ-PsTSFQ@mail.gmail.com>
On Tue, Jun 02, 2026 at 01:46:09PM -0700, Ackerley Tng wrote:
> Suzuki K Poulose <suzuki.poulose@arm.com> writes:
>
> > On 23/05/2026 01:17, Ackerley Tng via B4 Relay wrote:
> >> From: Ackerley Tng <ackerleytng@google.com>
> >>
> >> All-shared guest_memfd used to be only supported for non-CoCo VMs where
> >> preparation doesn't apply. INIT_SHARED is about to be supported for
> >> non-CoCo VMs in a later patch in this series.
> >
> > nit: s/non-CoCo/CoCo ?
> >
>
> Yes, thanks!
>
> >>
> >> In addition, KVM_SET_MEMORY_ATTRIBUTES2 is about to be supported in
> >> guest_memfd in a later patch in this series.
> >>
> >> This means that the kvm fault handler may now call kvm_gmem_get_pfn() on a
> >> shared folio for a CoCo VM where preparation applies.
> >>
> >> Add a check to make sure that preparation is only performed for private
> >> folios.
> >>
> >> Preparation will be undone on freeing (see kvm_gmem_free_folio()) and on
> >> conversion to shared.
> >>
> >> Signed-off-by: Michael Roth <michael.roth@amd.com>
> >
> > nit: Missing Co-Developed-by: ?
> >
>
> IIRC this should have been
>
> Suggested-by: Michael Roth <michael.roth@amd.com>
>
> IIRC Michael suggested this on one of the guest_memfd calls, Michael
> please let me know if you remember otherwise!
That rings a bell. Feel free to add, or just drop the stray SoB, either
way.
-Mike
>
> >>
> >> [...snip...]
> >>
^ permalink raw reply
* Re: [PATCH v7 07/42] KVM: guest_memfd: Only prepare folios for private pages
From: Michael Roth @ 2026-06-03 13:51 UTC (permalink / raw)
To: Suzuki K Poulose
Cc: Ackerley Tng, aik, andrew.jones, binbin.wu, brauner, chao.p.peng,
david, ira.weiny, jmattson, jthoughton, oupton, pankaj.gupta,
qperret, rick.p.edgecombe, rientjes, shivankg, steven.price,
tabba, willy, wyihan, yan.y.zhao, forkloop, pratyush,
aneesh.kumar, liam, Paolo Bonzini, Sean Christopherson,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Steven Rostedt, Masami Hiramatsu,
Mathieu Desnoyers, Jonathan Corbet, Shuah Khan, Shuah Khan,
Vishal Annapurve, Andrew Morton, Chris Li, Kairui Song,
Kemeng Shi, Nhat Pham, Baoquan He, Barry Song, Axel Rasmussen,
Yuanchu Xie, Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt,
Kiryl Shutsemau, Jason Gunthorpe, Vlastimil Babka, kvm,
linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest,
linux-mm, linux-coco
In-Reply-To: <88cae738-18e9-4ed3-8414-506a1ad8fb18@arm.com>
On Wed, Jun 03, 2026 at 09:58:45AM +0100, Suzuki K Poulose wrote:
> On 02/06/2026 23:41, Ackerley Tng wrote:
> > Suzuki K Poulose <suzuki.poulose@arm.com> writes:
> >
> > >
> > > [...snip...]
> > >
> > > > > @@ -914,7 +916,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct
> > > > > kvm_memory_slot *slot,
> > > > > folio_mark_uptodate(folio);
> > > > > }
> > > > > - r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio);
> > > > > + if (kvm_gmem_is_private_mem(inode, index))
> > > >
> > > > Don't we need to make sure the entire folio is private ? Not just the
> > > > page at the index ?
> > > > if (kvm_gmem_range_is_private(, index, folio_nr_pages(folio)) ?
> >
> > I was thinking to fix this when I do huge pages, for now guest_memfd is
> > always just PAGE_SIZE, so just looking up index is fine.
> >
> > Is that okay?
>
> Thats fine, but would be good to enforce that here, so that we don't miss
> out when we add support for multi page folios.
We sort of already enforce that in kvm_gmem_get_folio():
/*
* External interfaces like kvm_gmem_get_pfn() support dealing
* with hugepages to a degree, but internally, guest_memfd currently
* assumes that all folios are order-0 and handling would need
* to be updated for anything otherwise (e.g. page-clearing
* operations).
*/
WARN_ON_ONCE(!IS_ERR(folio) && folio_order(folio));
which was done as part of:
commit 6538b6221cc2feda415ca1946e66a5ef02dc6a0a
Author: Michael Roth <michael.roth@amd.com>
Date: Thu Jan 8 15:46:18 2026 -0600
KVM: guest_memfd: Remove partial hugepage handling from kvm_gmem_populate()
and that should trigger before you even reach the prepare path, so I think
that's covered.
In general, there some previous discussion where we decided we would stop wasting
time guessing at what we'll need to do for hugepages and instead just strip out
the partial support. Sean wanted the folio order kept at part of the internal API
since we know MMU will need that one way or another, but elsewhere within
guest_memfd we are okay to assume 4K. If we *know* certain points that will need
to change then a comment mentioning it isn't a bad idea, but even those comments
have tended to be wrong so far about exactly what changes are supposed to happen.
I'm not sure where the original discussion happened but there's some aftermath
discussion here[1] that I think summarizes current [non-]plans around
prepare+hugepages.
[1] https://lore.kernel.org/kvm/20250711163440.kwjebnzd7zeb4bxt@amd.com/
>
> >
> > >
> > > Or rather, we should go through the individual pages and apply the
> > > prepare for ones that are private ?
> > >
> > > Suzuki
> > >
> >
> > IIRC the plan was to make kvm_gmem_prepare_folio() idempotent, as in, if
> > a page is already private, just skip. Currently sev_gmem_prepare() does
> > a pr_debug(), which I guess is technically still idempotent.
> >
> > I'm thinking that the information tha needs tracking to make
> > .gmem_prepare() idempotent should be tracked by arch code.
> >
> > Does this work for ARM CCA?
>
> We don't hook into the prepare yet, but have plans to do that. We should
> be able to handle the pages that are already private. (For CCA context,
> RMI_GRANULE_DELEGATE_RANGE can skip over already REALM pages). So this
> should be fine.
>
> My point is, in a given folio, there may be pages that are shared.
> Like you said, this could be dealt with when we support hugepages.
Sounds good, that's also what SNP will do once hugepages come along.
-Mike
>
> Suzuki
>
>
> >
> > > >
> > > > [...snip...]
> > > >
>
^ permalink raw reply
* Re: [PATCH v14 06/44] arm64: RMI: Check for RMI support at init
From: Steven Price @ 2026-06-03 10:57 UTC (permalink / raw)
To: Marc Zyngier
Cc: kvm, kvmarm, Catalin Marinas, Will Deacon, James Morse,
Oliver Upton, Suzuki K Poulose, Zenghui Yu, linux-arm-kernel,
linux-kernel, Joey Gouly, Alexandru Elisei, Christoffer Dall,
Fuad Tabba, linux-coco, Ganapatrao Kulkarni, Gavin Shan,
Shanker Donthineni, Alper Gun, Aneesh Kumar K . V, Emi Kisanuki,
Vishal Annapurve, WeiLin.Chang, Lorenzo.Pieralisi2
In-Reply-To: <86bje8x6dj.wl-maz@kernel.org>
On 21/05/2026 14:02, Marc Zyngier wrote:
> On Wed, 13 May 2026 14:17:14 +0100,
> Steven Price <steven.price@arm.com> wrote:
>>
>> Query the RMI version number and check if it is a compatible version.
>> The first two feature registers are read and exposed for future code to
>> use.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> v14:
>> * This moves the basic RMI setup into the 'kernel' directory. This is
>> because RMI will be used for some features outside of KVM so should
>> be available even if KVM isn't compiled in.
>> ---
>> arch/arm64/include/asm/rmi_cmds.h | 3 ++
>> arch/arm64/kernel/Makefile | 2 +-
>> arch/arm64/kernel/cpufeature.c | 1 +
>> arch/arm64/kernel/rmi.c | 65 +++++++++++++++++++++++++++++++
>> 4 files changed, 70 insertions(+), 1 deletion(-)
>> create mode 100644 arch/arm64/kernel/rmi.c
>>
>> diff --git a/arch/arm64/include/asm/rmi_cmds.h b/arch/arm64/include/asm/rmi_cmds.h
>> index 04f7066894e9..9179934925c5 100644
>> --- a/arch/arm64/include/asm/rmi_cmds.h
>> +++ b/arch/arm64/include/asm/rmi_cmds.h
>> @@ -10,6 +10,9 @@
>>
>> #include <asm/rmi_smc.h>
>>
>> +extern unsigned long rmm_feat_reg0;
>> +extern unsigned long rmm_feat_reg1;
>> +
>> struct rtt_entry {
>> unsigned long walk_level;
>> unsigned long desc;
>> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
>> index 74b76bb70452..d68f351aae75 100644
>> --- a/arch/arm64/kernel/Makefile
>> +++ b/arch/arm64/kernel/Makefile
>> @@ -34,7 +34,7 @@ obj-y := debug-monitors.o entry.o irq.o fpsimd.o \
>> cpufeature.o alternative.o cacheinfo.o \
>> smp.o smp_spin_table.o topology.o smccc-call.o \
>> syscall.o proton-pack.o idle.o patching.o pi/ \
>> - rsi.o jump_label.o
>> + rsi.o jump_label.o rmi.o
>>
>> obj-$(CONFIG_COMPAT) += sys32.o signal32.o \
>> sys_compat.o
>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
>> index 6d53bb15cf7b..8bdd95a8c2de 100644
>> --- a/arch/arm64/kernel/cpufeature.c
>> +++ b/arch/arm64/kernel/cpufeature.c
>> @@ -292,6 +292,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar3[] = {
>> static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
>> ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV3_SHIFT, 4, 0),
>> ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV2_SHIFT, 4, 0),
>> + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_RME_SHIFT, 4, 0),
>> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_DIT_SHIFT, 4, 0),
>> ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_AMU_SHIFT, 4, 0),
>> ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_MPAM_SHIFT, 4, 0),
>> diff --git a/arch/arm64/kernel/rmi.c b/arch/arm64/kernel/rmi.c
>> new file mode 100644
>> index 000000000000..99c1ccc35c11
>> --- /dev/null
>> +++ b/arch/arm64/kernel/rmi.c
>> @@ -0,0 +1,65 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2023-2025 ARM Ltd.
>> + */
>> +
>> +#include <linux/memblock.h>
>> +
>> +#include <asm/rmi_cmds.h>
>> +
>> +unsigned long rmm_feat_reg0;
>> +unsigned long rmm_feat_reg1;
>
> What is the requirement for making those globally accessible? Can't
> they be made static and use an accessor that returns them? Can the
> variables be made __ro_after_init?
Good point - there's no requirement. Also the name isn't quite right -
these should be named rmi_ as there is a different set for RSI.
>> +
>> +static int rmi_check_version(void)
>> +{
>> + struct arm_smccc_res res;
>> + unsigned short version_major, version_minor;
>> + unsigned long host_version = RMI_ABI_VERSION(RMI_ABI_MAJOR_VERSION,
>> + RMI_ABI_MINOR_VERSION);
>> + unsigned long aa64pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
>> +
>> + /* If RME isn't supported, then RMI can't be */
>> + if (cpuid_feature_extract_unsigned_field(aa64pfr0, ID_AA64PFR0_EL1_RME_SHIFT) == 0)
>> + return -ENXIO;
>> +
>> + arm_smccc_1_1_invoke(SMC_RMI_VERSION, host_version, &res);
>> +
>> + if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
>> + return -ENXIO;
>> +
>> + version_major = RMI_ABI_VERSION_GET_MAJOR(res.a1);
>> + version_minor = RMI_ABI_VERSION_GET_MINOR(res.a1);
>> +
>> + if (res.a0 != RMI_SUCCESS) {
>> + unsigned short high_version_major, high_version_minor;
>> +
>> + high_version_major = RMI_ABI_VERSION_GET_MAJOR(res.a2);
>> + high_version_minor = RMI_ABI_VERSION_GET_MINOR(res.a2);
>> +
>> + pr_err("Unsupported RMI ABI (v%d.%d - v%d.%d) we want v%d.%d\n",
>> + version_major, version_minor,
>> + high_version_major, high_version_minor,
>> + RMI_ABI_MAJOR_VERSION,
>> + RMI_ABI_MINOR_VERSION);
>> + return -ENXIO;
>> + }
>> +
>> + pr_info("RMI ABI version %d.%d\n", version_major, version_minor);
>> +
>> + return 0;
>> +}
>> +
>> +static int __init arm64_init_rmi(void)
>> +{
>> + /* Continue without realm support if we can't agree on a version */
>> + if (rmi_check_version())
>> + return 0;
>> +
>> + if (WARN_ON(rmi_features(0, &rmm_feat_reg0)))
>> + return 0;
>> + if (WARN_ON(rmi_features(1, &rmm_feat_reg1)))
>> + return 0;
>> +
>> + return 0;
>> +}
>> +subsys_initcall(arm64_init_rmi);
>
> Is there any reliance on this being executed before or after KVM's own
> initialisation? If so, this should be captured.
Yes I'm expecting this to be called before KVM's initialisation.
kvm_init_rmi() alls rmi_is_available() to check if CCA is supported and
only enables the KVM side of things if that check passes. So if the
initialisation was the other way round then Realm guests would be
unsupported. I'll add a comment
/*
* Note arm64_init_rmi() must be called before kvm_init_rmi() otherwise KVM
* will not support realm guests. subsys_initcall() is called before
* module_init() (used for KVM) so this is OK.
*/
Thanks,
Steve
^ permalink raw reply
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