[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v5 3/4] xen: implement guest_physmap_pin_range and guest_physmap_unpin_range
guest_physmap_pin_range pins a range of guest pages so that their p2m mappings won't be changed. guest_physmap_unpin_range unpins the previously pinned pages. The pinning is done using one of the spare bits in the p2m ptes. Use the newly introduce p2m_walker to implement the two functions on ARM. Provide empty stubs for x86. Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> Changes in v5: - return -EBUSY when the P2M_DMA_PIN check fails; - rename _guest_physmap_pin_range to pin_one_pte; - rename _guest_physmap_unpin_range to unpin_one_pte. Changes in v4: - use p2m_walker to implement guest_physmap_pin_range and guest_physmap_unpin_range; - return -EINVAL when the P2M_DMA_PIN check fails; - change the printk into a gdprintk; - add a comment on what type of page can be pinned. --- xen/arch/arm/p2m.c | 48 ++++++++++++++++++++++++++++++++++++++++++++ xen/include/asm-arm/mm.h | 4 +++ xen/include/asm-arm/page.h | 7 +++++- xen/include/asm-x86/p2m.h | 12 +++++++++++ 4 files changed, 70 insertions(+), 1 deletions(-) diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index a9ceacf..bac6c7e 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -154,6 +154,46 @@ paddr_t p2m_lookup(struct domain *d, paddr_t paddr) return p2m.maddr; } +static int pin_one_pte(lpae_t *ptep, void *arg, int level) +{ + lpae_t pte = *ptep; + ASSERT(level == 3); + + if ( pte.p2m.avail & P2M_DMA_PIN ) + return -EBUSY; + pte.p2m.avail |= P2M_DMA_PIN; + write_pte(ptep, pte); + return 0; +} + +int guest_physmap_pin_range(struct domain *d, + xen_pfn_t gpfn, + unsigned int order) +{ + return p2m_walker(d, gpfn << PAGE_SHIFT, order, + pin_one_pte, NULL); +} + +static int unpin_one_pte(lpae_t *ptep, void *arg, int level) +{ + lpae_t pte = *ptep; + ASSERT(level == 3); + + if ( !pte.p2m.avail & P2M_DMA_PIN ) + return -EBUSY; + pte.p2m.avail &= ~P2M_DMA_PIN; + write_pte(ptep, pte); + return 0; +} + +int guest_physmap_unpin_range(struct domain *d, + xen_pfn_t gpfn, + unsigned int order) +{ + return p2m_walker(d, gpfn << PAGE_SHIFT, order, + unpin_one_pte, NULL); +} + int guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn, unsigned int order) @@ -263,6 +303,14 @@ static int create_p2m_entries(struct domain *d, cur_second_offset = second_table_offset(addr); } + if ( third[third_table_offset(addr)].p2m.avail & P2M_DMA_PIN ) + { + rc = -EINVAL; + gdprintk(XENLOG_WARNING, "cannot change p2m mapping for paddr=%"PRIpaddr + " domid=%d, the page is pinned\n", addr, d->domain_id); + goto out; + } + flush = third[third_table_offset(addr)].p2m.valid; /* Allocate a new RAM page and attach */ diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h index 0b0a457..d6ae3ad 100644 --- a/xen/include/asm-arm/mm.h +++ b/xen/include/asm-arm/mm.h @@ -314,6 +314,10 @@ void free_init_memory(void); int guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn, unsigned int order); +int guest_physmap_pin_range(struct domain *d, xen_pfn_t gpfn, + unsigned int order); +int guest_physmap_unpin_range(struct domain *d, xen_pfn_t gpfn, + unsigned int order); extern void put_page_type(struct page_info *page); static inline void put_page_and_type(struct page_info *page) diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h index 41e9eff..c08cfca 100644 --- a/xen/include/asm-arm/page.h +++ b/xen/include/asm-arm/page.h @@ -153,11 +153,16 @@ typedef struct { unsigned long hint:1; /* In a block of 16 contiguous entries */ unsigned long sbz2:1; unsigned long xn:1; /* eXecute-Never */ - unsigned long avail:4; /* Ignored by hardware */ + unsigned long avail:4; /* Ignored by hardware, see below */ unsigned long sbz1:5; } __attribute__((__packed__)) lpae_p2m_t; +/* Xen "avail" bits allocation in third level entries */ +#define P2M_DMA_PIN (1<<0) /* The page has been "pinned": the hypervisor + promises not to change the p2m mapping. + Only normal r/w guest RAM can be pinned. */ + /* * Walk is the common bits of p2m and pt entries which are needed to * simply walk the table (e.g. for debug). diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h index 43583b2..b08a722 100644 --- a/xen/include/asm-x86/p2m.h +++ b/xen/include/asm-x86/p2m.h @@ -492,6 +492,18 @@ void guest_physmap_remove_page(struct domain *d, /* Set a p2m range as populate-on-demand */ int guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn, unsigned int order); +static inline int guest_physmap_pin_range(struct domain *d, + xen_pfn_t gpfn, + unsigned int order) +{ + return -ENOSYS; +} +static inline int guest_physmap_unpin_range(struct domain *d, + xen_pfn_t gpfn, + unsigned int order) +{ + return -ENOSYS; +} /* Change types across all p2m entries in a domain */ void p2m_change_entry_type_global(struct domain *d, -- 1.7.2.5 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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