projects/linux·commit f2ecc964

Merge tag 'for-linus-5.19a-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

f2ecc964 · Linus Torvalds <[email protected]> · 2022-06-10 09:57:11 -07:00

Pull xen updates from Juergen Gross:

 - a small cleanup removing "export" of an __init function

 - a small series adding a new infrastructure for platform flags

 - a series adding generic virtio support for Xen guests (frontend side)

* tag 'for-linus-5.19a-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: unexport __init-annotated xen_xlate_map_ballooned_pages()
  arm/xen: Assign xen-grant DMA ops for xen-grant DMA devices
  xen/grant-dma-ops: Retrieve the ID of backend's domain for DT devices
  xen/grant-dma-iommu: Introduce stub IOMMU driver
  dt-bindings: Add xen,grant-dma IOMMU description for xen-grant DMA ops
  xen/virtio: Enable restricted memory access using Xen grant mappings
  xen/grant-dma-ops: Add option to restrict memory access under Xen
  xen/grants: support allocating consecutive grants
  arm/xen: Introduce xen_setup_dma_ops()
  virtio: replace arch_has_restricted_virtio_memory_access()
  kernel: add platform_has() infrastructure
Commit
f2ecc964b9414a407828f9bef242b77483e95a6d
Parents
7d78b7eb · dbac14a5

Merge commit. Changes below are compared with the first parent: 7d78b7eb.

Changes

32 files changed · +830 −85

FileStatusAddDelContent
Documentation/devicetree/bindings/iommu/xen,grant-dma.yamladded+39−0View file
MAINTAINERSmodified+8−0View file
arch/arm/include/asm/xen/xen-ops.hadded+2−0View file
arch/arm/mm/dma-mapping.cmodified+2−5View file
arch/arm/xen/enlighten.cmodified+2−0View file
arch/arm64/include/asm/xen/xen-ops.hadded+2−0View file
arch/arm64/mm/dma-mapping.cmodified+2−5View file
arch/s390/Kconfigmodified+0−1View file
arch/s390/mm/init.cmodified+3−10View file
arch/x86/Kconfigmodified+0−1View file
arch/x86/mm/mem_encrypt.cmodified+0−7View file
arch/x86/mm/mem_encrypt_amd.cmodified+4−0View file
arch/x86/xen/enlighten_hvm.cmodified+2−0View file
arch/x86/xen/enlighten_pv.cmodified+2−0View file
drivers/virtio/Kconfigmodified+0−6View file
drivers/virtio/virtio.cmodified+2−3View file
drivers/xen/Kconfigmodified+20−0View file
drivers/xen/Makefilemodified+2−0View file
drivers/xen/grant-dma-iommu.cadded+78−0View file
drivers/xen/grant-dma-ops.cadded+346−0View file
drivers/xen/grant-table.cmodified+215−36View file
drivers/xen/xlate_mmu.cmodified+0−1View file
include/asm-generic/Kbuildmodified+1−0View file
include/asm-generic/platform-feature.hadded+8−0View file
include/linux/platform-feature.hadded+19−0View file
include/linux/virtio_config.hmodified+0−9View file
include/xen/arm/xen-ops.hadded+18−0View file
include/xen/grant_table.hmodified+4−0View file
include/xen/xen-ops.hmodified+13−0View file
include/xen/xen.hmodified+8−0View file
kernel/Makefilemodified+1−1View file
kernel/platform-feature.cadded+27−0View file

Only the first 600 diff lines are shown. Download the complete patch.

Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml

View file
diff --git a/Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml b/Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml
new file mode 100644
index 0000000..be1539d
--- /dev/null
+++ b/Documentation/devicetree/bindings/iommu/xen,grant-dma.yaml
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iommu/xen,grant-dma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xen specific IOMMU for virtualized devices (e.g. virtio)
+
+maintainers:
+ - Stefano Stabellini <[email protected]>
+
+description:
+ The Xen IOMMU represents the Xen grant table interface. Grant mappings
+ are to be used with devices connected to the Xen IOMMU using the "iommus"
+ property, which also specifies the ID of the backend domain.
+ The binding is required to restrict memory access using Xen grant mappings.
+
+properties:
+ compatible:
+ const: xen,grant-dma
+
+ '#iommu-cells':
+ const: 1
+ description:
+ The single cell is the domid (domain ID) of the domain where the backend
+ is running.
+
+required:
+ - compatible
+ - "#iommu-cells"
+
+additionalProperties: false
+
+examples:
+ - |
+ iommu {
+ compatible = "xen,grant-dma";
+ #iommu-cells = <1>;
+ };

MAINTAINERS

View file
diff --git a/MAINTAINERS b/MAINTAINERS
index e42b5d0..f1947ba 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15831,6 +15831,14 @@ S: Maintained
F: Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.yaml
F: drivers/iio/chemical/pms7003.c
+PLATFORM FEATURE INFRASTRUCTURE
+M: Juergen Gross <[email protected]>
+S: Maintained
+F: arch/*/include/asm/platform-feature.h
+F: include/asm-generic/platform-feature.h
+F: include/linux/platform-feature.h
+F: kernel/platform-feature.c
+
PLDMFW LIBRARY
M: Jacob Keller <[email protected]>
S: Maintained

arch/arm/include/asm/xen/xen-ops.h

View file
diff --git a/arch/arm/include/asm/xen/xen-ops.h b/arch/arm/include/asm/xen/xen-ops.h
new file mode 100644
index 0000000..7ebb7eb
--- /dev/null
+++ b/arch/arm/include/asm/xen/xen-ops.h
@@ -0,0 +1,2 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <xen/arm/xen-ops.h>

arch/arm/mm/dma-mapping.c

View file
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 82ffac6..059cce0 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -33,7 +33,7 @@
#include <asm/dma-iommu.h>
#include <asm/mach/map.h>
#include <asm/system_info.h>
-#include <xen/swiotlb-xen.h>
+#include <asm/xen/xen-ops.h>
#include "dma.h"
#include "mm.h"
@@ -2287,10 +2287,7 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
set_dma_ops(dev, dma_ops);
-#ifdef CONFIG_XEN
- if (xen_initial_domain())
- dev->dma_ops = &xen_swiotlb_dma_ops;
-#endif
+ xen_setup_dma_ops(dev);
dev->archdata.dma_ops_setup = true;
}

arch/arm/xen/enlighten.c

View file
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 07eb69f..1f9c3ba 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -443,6 +443,8 @@ static int __init xen_guest_init(void)
if (!xen_domain())
return 0;
+ xen_set_restricted_virtio_memory_access();
+
if (!acpi_disabled)
xen_acpi_guest_init();
else

arch/arm64/include/asm/xen/xen-ops.h

View file
diff --git a/arch/arm64/include/asm/xen/xen-ops.h b/arch/arm64/include/asm/xen/xen-ops.h
new file mode 100644
index 0000000..7ebb7eb
--- /dev/null
+++ b/arch/arm64/include/asm/xen/xen-ops.h
@@ -0,0 +1,2 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <xen/arm/xen-ops.h>

arch/arm64/mm/dma-mapping.c

View file
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 6719f9e..6099c81 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -9,9 +9,9 @@
#include <linux/dma-map-ops.h>
#include <linux/dma-iommu.h>
#include <xen/xen.h>
-#include <xen/swiotlb-xen.h>
#include <asm/cacheflush.h>
+#include <asm/xen/xen-ops.h>
void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
@@ -52,8 +52,5 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
if (iommu)
iommu_setup_dma_ops(dev, dma_base, dma_base + size - 1);
-#ifdef CONFIG_XEN
- if (xen_swiotlb_detect())
- dev->dma_ops = &xen_swiotlb_dma_ops;
-#endif
+ xen_setup_dma_ops(dev);
}

arch/s390/Kconfig

View file
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 5126a5d..91c0b80 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -769,7 +769,6 @@ menu "Virtualization"
config PROTECTED_VIRTUALIZATION_GUEST
def_bool n
prompt "Protected virtualization guest support"
- select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
help
Select this option, if you want to be able to run this
kernel as a protected virtualization KVM guest.

arch/s390/mm/init.c

View file
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 6fb6bf6..6a0ac00 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -31,6 +31,7 @@
#include <linux/cma.h>
#include <linux/gfp.h>
#include <linux/dma-direct.h>
+#include <linux/platform-feature.h>
#include <asm/processor.h>
#include <linux/uaccess.h>
#include <asm/pgalloc.h>
@@ -168,22 +169,14 @@ bool force_dma_unencrypted(struct device *dev)
return is_prot_virt_guest();
}
-#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
-
-int arch_has_restricted_virtio_memory_access(void)
-{
- return is_prot_virt_guest();
-}
-EXPORT_SYMBOL(arch_has_restricted_virtio_memory_access);
-
-#endif
-
/* protected virtualization */
static void pv_init(void)
{
if (!is_prot_virt_guest())
return;
+ platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
+
/* make sure bounce buffers are shared */
swiotlb_init(true, SWIOTLB_FORCE | SWIOTLB_VERBOSE);
swiotlb_update_mem_attributes();

arch/x86/Kconfig

View file
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9783ebc..be0b95e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1542,7 +1542,6 @@ config X86_CPA_STATISTICS
config X86_MEM_ENCRYPT
select ARCH_HAS_FORCE_DMA_UNENCRYPTED
select DYNAMIC_PHYSICAL_MASK
- select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
def_bool n
config AMD_MEM_ENCRYPT

arch/x86/mm/mem_encrypt.c

View file
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 11350e2..9f27e14 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -12,7 +12,6 @@
#include <linux/swiotlb.h>
#include <linux/cc_platform.h>
#include <linux/mem_encrypt.h>
-#include <linux/virtio_config.h>
/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
bool force_dma_unencrypted(struct device *dev)
@@ -87,9 +86,3 @@ void __init mem_encrypt_init(void)
print_mem_encrypt_feature_info();
}
-
-int arch_has_restricted_virtio_memory_access(void)
-{
- return cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT);
-}
-EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access);

arch/x86/mm/mem_encrypt_amd.c

View file
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index e8f7953..f6d038e 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -21,6 +21,7 @@
#include <linux/dma-mapping.h>
#include <linux/virtio_config.h>
#include <linux/cc_platform.h>
+#include <linux/platform-feature.h>
#include <asm/tlbflush.h>
#include <asm/fixmap.h>
@@ -242,6 +243,9 @@ void __init sev_setup_arch(void)
size = total_mem * 6 / 100;
size = clamp_val(size, IO_TLB_DEFAULT_SIZE, SZ_1G);
swiotlb_adjust_size(size);
+
+ /* Set restricted memory access for virtio. */
+ platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
}
static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)

arch/x86/xen/enlighten_hvm.c

View file
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 517a9d8..8b71b1d 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -195,6 +195,8 @@ static void __init xen_hvm_guest_init(void)
if (xen_pv_domain())
return;
+ xen_set_restricted_virtio_memory_access();
+
init_hvm_pv_info();
reserve_shared_info();

arch/x86/xen/enlighten_pv.c

View file
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index f33a442..e3297b1 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -109,6 +109,8 @@ static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
static void __init xen_pv_init_platform(void)
{
+ xen_set_restricted_virtio_memory_access();
+
populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);

drivers/virtio/Kconfig

View file
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index b5adf6a..a6dc8b5 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -6,12 +6,6 @@ config VIRTIO
bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
or CONFIG_S390_GUEST.
-config ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
- bool
- help
- This option is selected if the architecture may need to enforce
- VIRTIO_F_ACCESS_PLATFORM
-
config VIRTIO_PCI_LIB
tristate
help

drivers/virtio/virtio.c

View file
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index ef04a96..6bace84 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -5,6 +5,7 @@
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/of.h>
+#include <linux/platform-feature.h>
#include <uapi/linux/virtio_ids.h>
/* Unique numbering for virtio devices. */
@@ -170,12 +171,10 @@ EXPORT_SYMBOL_GPL(virtio_add_status);
static int virtio_features_ok(struct virtio_device *dev)
{
unsigned int status;
- int ret;
might_sleep();
- ret = arch_has_restricted_virtio_memory_access();
- if (ret) {
+ if (platform_has(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS)) {
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
dev_warn(&dev->dev,
"device must provide VIRTIO_F_VERSION_1\n");

drivers/xen/Kconfig

View file
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 120d32f..bfd5f4f 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -335,4 +335,24 @@ config XEN_UNPOPULATED_ALLOC
having to balloon out RAM regions in order to obtain physical memory
space to create such mappings.
+config XEN_GRANT_DMA_IOMMU
+ bool
+ select IOMMU_API
+
+config XEN_GRANT_DMA_OPS
+ bool
+ select DMA_OPS
+
+config XEN_VIRTIO
+ bool "Xen virtio support"
+ depends on VIRTIO
+ select XEN_GRANT_DMA_OPS
+ select XEN_GRANT_DMA_IOMMU if OF
+ help
+ Enable virtio support for running as Xen guest. Depending on the
+ guest type this will require special support on the backend side
+ (qemu or kernel, depending on the virtio device types used).
+
+ If in doubt, say n.
+
endmenu

drivers/xen/Makefile

View file
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 5aae66e..c0503f1 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -39,3 +39,5 @@ xen-gntalloc-y := gntalloc.o
xen-privcmd-y := privcmd.o privcmd-buf.o
obj-$(CONFIG_XEN_FRONT_PGDIR_SHBUF) += xen-front-pgdir-shbuf.o
obj-$(CONFIG_XEN_UNPOPULATED_ALLOC) += unpopulated-alloc.o
+obj-$(CONFIG_XEN_GRANT_DMA_OPS) += grant-dma-ops.o
+obj-$(CONFIG_XEN_GRANT_DMA_IOMMU) += grant-dma-iommu.o

drivers/xen/grant-dma-iommu.c

View file
diff --git a/drivers/xen/grant-dma-iommu.c b/drivers/xen/grant-dma-iommu.c
new file mode 100644
index 0000000..16b8bc0
--- /dev/null
+++ b/drivers/xen/grant-dma-iommu.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Stub IOMMU driver which does nothing.
+ * The main purpose of it being present is to reuse generic IOMMU device tree
+ * bindings by Xen grant DMA-mapping layer.
+ *
+ * Copyright (C) 2022 EPAM Systems Inc.
+ */
+
+#include <linux/iommu.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+struct grant_dma_iommu_device {
+ struct device *dev;
+ struct iommu_device iommu;
+};
+
+/* Nothing is really needed here */
+static const struct iommu_ops grant_dma_iommu_ops;
+
+static const struct of_device_id grant_dma_iommu_of_match[] = {
+ { .compatible = "xen,grant-dma" },
+ { },
+};
+
+static int grant_dma_iommu_probe(struct platform_device *pdev)
+{
+ struct grant_dma_iommu_device *mmu;
+ int ret;
+
+ mmu = devm_kzalloc(&pdev->dev, sizeof(*mmu), GFP_KERNEL);
+ if (!mmu)
+ return -ENOMEM;
+
+ mmu->dev = &pdev->dev;
+
+ ret = iommu_device_register(&mmu->iommu, &grant_dma_iommu_ops, &pdev->dev);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, mmu);
+
+ return 0;
+}
+
+static int grant_dma_iommu_remove(struct platform_device *pdev)
+{
+ struct grant_dma_iommu_device *mmu = platform_get_drvdata(pdev);
+
+ platform_set_drvdata(pdev, NULL);
+ iommu_device_unregister(&mmu->iommu);
+
+ return 0;
+}
+
+static struct platform_driver grant_dma_iommu_driver = {
+ .driver = {
+ .name = "grant-dma-iommu",
+ .of_match_table = grant_dma_iommu_of_match,
+ },
+ .probe = grant_dma_iommu_probe,
+ .remove = grant_dma_iommu_remove,
+};
+
+static int __init grant_dma_iommu_init(void)
+{
+ struct device_node *iommu_np;
+
+ iommu_np = of_find_matching_node(NULL, grant_dma_iommu_of_match);
+ if (!iommu_np)
+ return 0;
+
+ of_node_put(iommu_np);
+
+ return platform_driver_register(&grant_dma_iommu_driver);
+}
+subsys_initcall(grant_dma_iommu_init);

drivers/xen/grant-dma-ops.c

View file
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
new file mode 100644
index 0000000..fc01424
--- /dev/null
+++ b/drivers/xen/grant-dma-ops.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Xen grant DMA-mapping layer - contains special DMA-mapping routines
+ * for providing grant references as DMA addresses to be used by frontends
+ * (e.g. virtio) in Xen guests
+ *
+ * Copyright (c) 2021, Juergen Gross <[email protected]>
+ */
+
+#include <linux/module.h>
+#include <linux/dma-map-ops.h>
+#include <linux/of.h>
+#include <linux/pfn.h>
+#include <linux/xarray.h>
+#include <xen/xen.h>
+#include <xen/xen-ops.h>
+#include <xen/grant_table.h>
+
+struct xen_grant_dma_data {
+ /* The ID of backend domain */
+ domid_t backend_domid;
+ /* Is device behaving sane? */
+ bool broken;
+};
+
+static DEFINE_XARRAY(xen_grant_dma_devices);
+
+#define XEN_GRANT_DMA_ADDR_OFF (1ULL << 63)
+
+static inline dma_addr_t grant_to_dma(grant_ref_t grant)
+{
+ return XEN_GRANT_DMA_ADDR_OFF | ((dma_addr_t)grant << PAGE_SHIFT);
+}
+
+static inline grant_ref_t dma_to_grant(dma_addr_t dma)
+{
+ return (grant_ref_t)((dma & ~XEN_GRANT_DMA_ADDR_OFF) >> PAGE_SHIFT);
+}
+
+static struct xen_grant_dma_data *find_xen_grant_dma_data(struct device *dev)
+{
+ struct xen_grant_dma_data *data;
+
+ xa_lock(&xen_grant_dma_devices);
+ data = xa_load(&xen_grant_dma_devices, (unsigned long)dev);
+ xa_unlock(&xen_grant_dma_devices);
+
+ return data;
+}
+
+/*
+ * DMA ops for Xen frontends (e.g. virtio).
+ *
+ * Used to act as a kind of software IOMMU for Xen guests by using grants as
+ * DMA addresses.
+ * Such a DMA address is formed by using the grant reference as a frame
+ * number and setting the highest address bit (this bit is for the backend
+ * to be able to distinguish it from e.g. a mmio address).
+ */
+static void *xen_grant_dma_alloc(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t gfp,
+ unsigned long attrs)
+{
+ struct xen_grant_dma_data *data;
+ unsigned int i, n_pages = PFN_UP(size);
+ unsigned long pfn;
+ grant_ref_t grant;
+ void *ret;
+
+ data = find_xen_grant_dma_data(dev);
+ if (!data)
+ return NULL;
+
+ if (unlikely(data->broken))
+ return NULL;
+
+ ret = alloc_pages_exact(n_pages * PAGE_SIZE, gfp);
+ if (!ret)
+ return NULL;
+
+ pfn = virt_to_pfn(ret);
+
+ if (gnttab_alloc_grant_reference_seq(n_pages, &grant)) {
+ free_pages_exact(ret, n_pages * PAGE_SIZE);
+ return NULL;
+ }
+
+ for (i = 0; i < n_pages; i++) {
+ gnttab_grant_foreign_access_ref(grant + i, data->backend_domid,
+ pfn_to_gfn(pfn + i), 0);
+ }
+
+ *dma_handle = grant_to_dma(grant);
+
+ return ret;
+}
+
+static void xen_grant_dma_free(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_handle, unsigned long attrs)
+{
+ struct xen_grant_dma_data *data;
+ unsigned int i, n_pages = PFN_UP(size);
+ grant_ref_t grant;
+
+ data = find_xen_grant_dma_data(dev);
+ if (!data)
+ return;
+
+ if (unlikely(data->broken))
+ return;
+
+ grant = dma_to_grant(dma_handle);
+
+ for (i = 0; i < n_pages; i++) {
+ if (unlikely(!gnttab_end_foreign_access_ref(grant + i))) {
+ dev_alert(dev, "Grant still in use by backend domain, disabled for further use\n");
+ data->broken = true;
+ return;
+ }
+ }
+
+ gnttab_free_grant_reference_seq(grant, n_pages);
+
+ free_pages_exact(vaddr, n_pages * PAGE_SIZE);
+}
+
+static struct page *xen_grant_dma_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle,
+ enum dma_data_direction dir,
+ gfp_t gfp)
+{
+ void *vaddr;
+
+ vaddr = xen_grant_dma_alloc(dev, size, dma_handle, gfp, 0);
+ if (!vaddr)
+ return NULL;
+
+ return virt_to_page(vaddr);
+}
+
+static void xen_grant_dma_free_pages(struct device *dev, size_t size,
+ struct page *vaddr, dma_addr_t dma_handle,
+ enum dma_data_direction dir)
+{
+ xen_grant_dma_free(dev, size, page_to_virt(vaddr), dma_handle, 0);
+}
+
+static dma_addr_t xen_grant_dma_map_page(struct device *dev, struct page *page,
+ unsigned long offset, size_t size,
+ enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ struct xen_grant_dma_data *data;
+ unsigned int i, n_pages = PFN_UP(size);

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drivers/xen/grant-table.c

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drivers/xen/xlate_mmu.c

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include/asm-generic/Kbuild

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include/asm-generic/platform-feature.h

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include/linux/platform-feature.h

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include/linux/virtio_config.h

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include/xen/arm/xen-ops.h

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include/xen/grant_table.h

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include/xen/xen-ops.h

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include/xen/xen.h

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kernel/Makefile

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kernel/platform-feature.c

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