[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 09/11] xen/arm: Add relinquish_p2m_mapping to remove reference on every mapped page
This function will be called when the domain relinquishes its memory. It removes refcount on every mapped page to a valid MFN. Currently, Xen doesn't take reference on every new mapping but only for foreign mapping. Restrict the function only on foreign mapping. Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx> --- Changes in v4: - Use LPAE_ENTRIES instead of hardcoded value Changes in v3: - Rework title - Reuse create_p2m_entries to remove reference - Don't forget to set relmem! - Fix compilation (missing include) Changes in v2: - Introduce the patch --- xen/arch/arm/domain.c | 8 ++++++++ xen/arch/arm/p2m.c | 44 +++++++++++++++++++++++++++++++++++++++++- xen/include/asm-arm/domain.h | 1 + xen/include/asm-arm/p2m.h | 15 ++++++++++++++ 4 files changed, 67 insertions(+), 1 deletion(-) diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c index 1590708..4099e88 100644 --- a/xen/arch/arm/domain.c +++ b/xen/arch/arm/domain.c @@ -717,6 +717,14 @@ int domain_relinquish_resources(struct domain *d) if ( ret ) return ret; + d->arch.relmem = RELMEM_mapping; + /* Fallthrough */ + + case RELMEM_mapping: + ret = relinquish_p2m_mapping(d); + if ( ret ) + return ret; + d->arch.relmem = RELMEM_done; /* Fallthrough */ diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index cfdc19c..cf2e178 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -6,6 +6,8 @@ #include <xen/bitops.h> #include <asm/flushtlb.h> #include <asm/gic.h> +#include <asm/event.h> +#include <asm/hardirq.h> /* First level P2M is 2 consecutive pages */ #define P2M_FIRST_ORDER 1 @@ -213,7 +215,8 @@ static int p2m_create_table(struct domain *d, enum p2m_operation { INSERT, ALLOCATE, - REMOVE + REMOVE, + RELINQUISH, }; static int create_p2m_entries(struct domain *d, @@ -231,6 +234,7 @@ static int create_p2m_entries(struct domain *d, unsigned long cur_first_page = ~0, cur_first_offset = ~0, cur_second_offset = ~0; + unsigned long count = 0; spin_lock(&p2m->lock); @@ -315,6 +319,7 @@ static int create_p2m_entries(struct domain *d, maddr += PAGE_SIZE; } break; + case RELINQUISH: case REMOVE: { lpae_t pte = third[third_table_offset(addr)]; @@ -338,6 +343,29 @@ static int create_p2m_entries(struct domain *d, if ( flush ) flush_tlb_all_local(); + + + count++; + + if ( op == RELINQUISH && count == LPAE_ENTRIES && + hypercall_preempt_check() ) + { + p2m->next_gfn_to_relinquish = maddr >> PAGE_SHIFT; + rc = -EAGAIN; + goto out; + } + } + + /* When the function will remove mapping, p2m type should always + * be p2m_invalid. */ + if ( (t == p2m_ram_rw) || (t == p2m_ram_ro) || (t == p2m_map_foreign)) + { + unsigned long sgfn = paddr_to_pfn(start_gpaddr); + unsigned long egfn = paddr_to_pfn(end_gpaddr); + + p2m->max_mapped_gfn = MAX(p2m->max_mapped_gfn, egfn); + /* Use next_gfn_to_relinquish to store the lowest gfn mapped */ + p2m->next_gfn_to_relinquish = MIN(p2m->next_gfn_to_relinquish, sgfn); } rc = 0; @@ -533,12 +561,26 @@ int p2m_init(struct domain *d) p2m->first_level = NULL; + p2m->max_mapped_gfn = 0; + p2m->next_gfn_to_relinquish = ULONG_MAX; + err: spin_unlock(&p2m->lock); return rc; } +int relinquish_p2m_mapping(struct domain *d) +{ + struct p2m_domain *p2m = &d->arch.p2m; + + return create_p2m_entries(d, RELINQUISH, + pfn_to_paddr(p2m->next_gfn_to_relinquish), + pfn_to_paddr(p2m->max_mapped_gfn), + pfn_to_paddr(INVALID_MFN), + MATTR_MEM, p2m_invalid); +} + unsigned long gmfn_to_mfn(struct domain *d, unsigned long gpfn) { paddr_t p = p2m_lookup(d, pfn_to_paddr(gpfn), NULL); diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h index 53c9895..28d39a0 100644 --- a/xen/include/asm-arm/domain.h +++ b/xen/include/asm-arm/domain.h @@ -112,6 +112,7 @@ struct arch_domain RELMEM_not_started, RELMEM_xen, RELMEM_page, + RELMEM_mapping, RELMEM_done, } relmem; diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h index 844ef9d..dc9d058 100644 --- a/xen/include/asm-arm/p2m.h +++ b/xen/include/asm-arm/p2m.h @@ -18,6 +18,15 @@ struct p2m_domain { /* Current VMID in use */ uint8_t vmid; + + /* Highest guest frame that's ever been mapped in the p2m + * Take only into account ram and foreign mapping + */ + unsigned long max_mapped_gfn; + + /* When releasing mapped gfn's in a preemptible manner, recall where + * to resume the search */ + unsigned long next_gfn_to_relinquish; }; /* List of possible type for each page in the p2m entry. @@ -48,6 +57,12 @@ int p2m_init(struct domain *d); /* Return all the p2m resources to Xen. */ void p2m_teardown(struct domain *d); +/* Remove mapping refcount on each mapping page in the p2m + * + * TODO: For the moment only foreign mapping is handled + */ +int relinquish_p2m_mapping(struct domain *d); + /* Allocate a new p2m table for a domain. * * Returns 0 for success or -errno. -- 1.7.10.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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