From 4a19138c6505e224d9f4cc2fe9ada9188d7100ea Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 17 Oct 2013 16:22:27 +0000 Subject: 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 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. --- arch/arm/include/asm/xen/page.h | 49 +++++++++++++++++++++++++++++++++++------ 1 file changed, 42 insertions(+), 7 deletions(-) (limited to 'arch/arm/include') 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 #include +#include #include -#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) { -- cgit v1.2.3