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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2013-10-17 16:22:27 +0000
committerStefano Stabellini <stefano.stabellini@eu.citrix.com>2013-10-17 16:22:27 +0000
commit4a19138c6505e224d9f4cc2fe9ada9188d7100ea (patch)
treecff1b72f69858d6bdfb0486e082de13e8b93f9dc /arch
parentarm64: define DMA_ERROR_CODE (diff)
downloadlinux-dev-4a19138c6505e224d9f4cc2fe9ada9188d7100ea.tar.xz
linux-dev-4a19138c6505e224d9f4cc2fe9ada9188d7100ea.zip
arm/xen,arm64/xen: introduce p2m
Introduce physical to machine and machine to physical tracking mechanisms based on rbtrees for arm/xen and arm64/xen. We need it because any guests on ARM are an autotranslate guests, therefore a physical address is potentially different from a machine address. When programming a device to do DMA, we need to be extra-careful to use machine addresses rather than physical addresses to program the device. Therefore we need to know the physical to machine mappings. For the moment we assume that dom0 starts with a 1:1 physical to machine mapping, in other words physical addresses correspond to machine addresses. However when mapping a foreign grant reference, obviously the 1:1 model doesn't work anymore. So at the very least we need to be able to track grant mappings. We need locking to protect accesses to the two trees. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Changes in v8: - move pfn_to_mfn and mfn_to_pfn to page.h as static inline functions; - no need to walk the tree if phys_to_mach.rb_node is NULL; - correctly handle multipage p2m entries; - substitute the spin_lock with a rwlock.
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/include/asm/xen/page.h49
-rw-r--r--arch/arm/xen/Makefile2
-rw-r--r--arch/arm/xen/p2m.c208
-rw-r--r--arch/arm64/xen/Makefile2
4 files changed, 252 insertions, 9 deletions
diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index 359a7b50b158..d1b5dd566472 100644
--- a/arch/arm/include/asm/xen/page.h
+++ b/arch/arm/include/asm/xen/page.h
@@ -7,11 +7,10 @@
#include <linux/pfn.h>
#include <linux/types.h>
+#include <xen/xen.h>
#include <xen/interface/grant_table.h>
-#define pfn_to_mfn(pfn) (pfn)
#define phys_to_machine_mapping_valid(pfn) (1)
-#define mfn_to_pfn(mfn) (mfn)
#define mfn_to_virt(m) (__va(mfn_to_pfn(m) << PAGE_SHIFT))
#define pte_mfn pte_pfn
@@ -32,6 +31,44 @@ typedef struct xpaddr {
#define INVALID_P2M_ENTRY (~0UL)
+unsigned long __pfn_to_mfn(unsigned long pfn);
+unsigned long __mfn_to_pfn(unsigned long mfn);
+extern struct rb_root phys_to_mach;
+
+static inline unsigned long pfn_to_mfn(unsigned long pfn)
+{
+ unsigned long mfn;
+
+ if (phys_to_mach.rb_node != NULL) {
+ mfn = __pfn_to_mfn(pfn);
+ if (mfn != INVALID_P2M_ENTRY)
+ return mfn;
+ }
+
+ if (xen_initial_domain())
+ return pfn;
+ else
+ return INVALID_P2M_ENTRY;
+}
+
+static inline unsigned long mfn_to_pfn(unsigned long mfn)
+{
+ unsigned long pfn;
+
+ if (phys_to_mach.rb_node != NULL) {
+ pfn = __mfn_to_pfn(mfn);
+ if (pfn != INVALID_P2M_ENTRY)
+ return pfn;
+ }
+
+ if (xen_initial_domain())
+ return mfn;
+ else
+ return INVALID_P2M_ENTRY;
+}
+
+#define mfn_to_local_pfn(mfn) mfn_to_pfn(mfn)
+
static inline xmaddr_t phys_to_machine(xpaddr_t phys)
{
unsigned offset = phys.paddr & ~PAGE_MASK;
@@ -76,11 +113,9 @@ static inline int m2p_remove_override(struct page *page, bool clear_pte)
return 0;
}
-static inline bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
-{
- BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
- return true;
-}
+bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
+bool __set_phys_to_machine_multi(unsigned long pfn, unsigned long mfn,
+ unsigned long nr_pages);
static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
diff --git a/arch/arm/xen/Makefile b/arch/arm/xen/Makefile
index 43841033afd3..21e6ff503178 100644
--- a/arch/arm/xen/Makefile
+++ b/arch/arm/xen/Makefile
@@ -1 +1 @@
-obj-y := enlighten.o hypercall.o grant-table.o
+obj-y := enlighten.o hypercall.o grant-table.o p2m.o
diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c
new file mode 100644
index 000000000000..5df4a9afb8c6
--- /dev/null
+++ b/arch/arm/xen/p2m.c
@@ -0,0 +1,208 @@
+#include <linux/bootmem.h>
+#include <linux/gfp.h>
+#include <linux/export.h>
+#include <linux/rwlock.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
+#include <linux/swiotlb.h>
+
+#include <xen/xen.h>
+#include <xen/interface/memory.h>
+#include <xen/swiotlb-xen.h>
+
+#include <asm/cacheflush.h>
+#include <asm/xen/page.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/interface.h>
+
+struct xen_p2m_entry {
+ unsigned long pfn;
+ unsigned long mfn;
+ unsigned long nr_pages;
+ struct rb_node rbnode_mach;
+ struct rb_node rbnode_phys;
+};
+
+rwlock_t p2m_lock;
+struct rb_root phys_to_mach = RB_ROOT;
+static struct rb_root mach_to_phys = RB_ROOT;
+
+static int xen_add_phys_to_mach_entry(struct xen_p2m_entry *new)
+{
+ struct rb_node **link = &phys_to_mach.rb_node;
+ struct rb_node *parent = NULL;
+ struct xen_p2m_entry *entry;
+ int rc = 0;
+
+ while (*link) {
+ parent = *link;
+ entry = rb_entry(parent, struct xen_p2m_entry, rbnode_phys);
+
+ if (new->mfn == entry->mfn)
+ goto err_out;
+ if (new->pfn == entry->pfn)
+ goto err_out;
+
+ if (new->pfn < entry->pfn)
+ link = &(*link)->rb_left;
+ else
+ link = &(*link)->rb_right;
+ }
+ rb_link_node(&new->rbnode_phys, parent, link);
+ rb_insert_color(&new->rbnode_phys, &phys_to_mach);
+ goto out;
+
+err_out:
+ rc = -EINVAL;
+ pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
+ __func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
+out:
+ return rc;
+}
+
+unsigned long __pfn_to_mfn(unsigned long pfn)
+{
+ struct rb_node *n = phys_to_mach.rb_node;
+ struct xen_p2m_entry *entry;
+ unsigned long irqflags;
+
+ read_lock_irqsave(&p2m_lock, irqflags);
+ while (n) {
+ entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
+ if (entry->pfn <= pfn &&
+ entry->pfn + entry->nr_pages > pfn) {
+ read_unlock_irqrestore(&p2m_lock, irqflags);
+ return entry->mfn + (pfn - entry->pfn);
+ }
+ if (pfn < entry->pfn)
+ n = n->rb_left;
+ else
+ n = n->rb_right;
+ }
+ read_unlock_irqrestore(&p2m_lock, irqflags);
+
+ return INVALID_P2M_ENTRY;
+}
+EXPORT_SYMBOL_GPL(__pfn_to_mfn);
+
+static int xen_add_mach_to_phys_entry(struct xen_p2m_entry *new)
+{
+ struct rb_node **link = &mach_to_phys.rb_node;
+ struct rb_node *parent = NULL;
+ struct xen_p2m_entry *entry;
+ int rc = 0;
+
+ while (*link) {
+ parent = *link;
+ entry = rb_entry(parent, struct xen_p2m_entry, rbnode_mach);
+
+ if (new->mfn == entry->mfn)
+ goto err_out;
+ if (new->pfn == entry->pfn)
+ goto err_out;
+
+ if (new->mfn < entry->mfn)
+ link = &(*link)->rb_left;
+ else
+ link = &(*link)->rb_right;
+ }
+ rb_link_node(&new->rbnode_mach, parent, link);
+ rb_insert_color(&new->rbnode_mach, &mach_to_phys);
+ goto out;
+
+err_out:
+ rc = -EINVAL;
+ pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
+ __func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
+out:
+ return rc;
+}
+
+unsigned long __mfn_to_pfn(unsigned long mfn)
+{
+ struct rb_node *n = mach_to_phys.rb_node;
+ struct xen_p2m_entry *entry;
+ unsigned long irqflags;
+
+ read_lock_irqsave(&p2m_lock, irqflags);
+ while (n) {
+ entry = rb_entry(n, struct xen_p2m_entry, rbnode_mach);
+ if (entry->mfn <= mfn &&
+ entry->mfn + entry->nr_pages > mfn) {
+ read_unlock_irqrestore(&p2m_lock, irqflags);
+ return entry->pfn + (mfn - entry->mfn);
+ }
+ if (mfn < entry->mfn)
+ n = n->rb_left;
+ else
+ n = n->rb_right;
+ }
+ read_unlock_irqrestore(&p2m_lock, irqflags);
+
+ return INVALID_P2M_ENTRY;
+}
+EXPORT_SYMBOL_GPL(__mfn_to_pfn);
+
+bool __set_phys_to_machine_multi(unsigned long pfn,
+ unsigned long mfn, unsigned long nr_pages)
+{
+ int rc;
+ unsigned long irqflags;
+ struct xen_p2m_entry *p2m_entry;
+ struct rb_node *n = phys_to_mach.rb_node;
+
+ if (mfn == INVALID_P2M_ENTRY) {
+ write_lock_irqsave(&p2m_lock, irqflags);
+ while (n) {
+ p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
+ if (p2m_entry->pfn <= pfn &&
+ p2m_entry->pfn + p2m_entry->nr_pages > pfn) {
+ rb_erase(&p2m_entry->rbnode_mach, &mach_to_phys);
+ rb_erase(&p2m_entry->rbnode_phys, &phys_to_mach);
+ write_unlock_irqrestore(&p2m_lock, irqflags);
+ kfree(p2m_entry);
+ return true;
+ }
+ if (pfn < p2m_entry->pfn)
+ n = n->rb_left;
+ else
+ n = n->rb_right;
+ }
+ write_unlock_irqrestore(&p2m_lock, irqflags);
+ return true;
+ }
+
+ p2m_entry = kzalloc(sizeof(struct xen_p2m_entry), GFP_NOWAIT);
+ if (!p2m_entry) {
+ pr_warn("cannot allocate xen_p2m_entry\n");
+ return false;
+ }
+ p2m_entry->pfn = pfn;
+ p2m_entry->nr_pages = nr_pages;
+ p2m_entry->mfn = mfn;
+
+ write_lock_irqsave(&p2m_lock, irqflags);
+ if ((rc = xen_add_phys_to_mach_entry(p2m_entry) < 0) ||
+ (rc = xen_add_mach_to_phys_entry(p2m_entry) < 0)) {
+ write_unlock_irqrestore(&p2m_lock, irqflags);
+ return false;
+ }
+ write_unlock_irqrestore(&p2m_lock, irqflags);
+ return true;
+}
+EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
+
+bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+ return __set_phys_to_machine_multi(pfn, mfn, 1);
+}
+EXPORT_SYMBOL_GPL(__set_phys_to_machine);
+
+int p2m_init(void)
+{
+ rwlock_init(&p2m_lock);
+ return 0;
+}
+arch_initcall(p2m_init);
diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
index be240404ba96..cd866b0c619b 100644
--- a/arch/arm64/xen/Makefile
+++ b/arch/arm64/xen/Makefile
@@ -1,2 +1,2 @@
-xen-arm-y += $(addprefix ../../arm/xen/, enlighten.o grant-table.o)
+xen-arm-y += $(addprefix ../../arm/xen/, enlighten.o grant-table.o p2m.o)
obj-y := xen-arm.o hypercall.o