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xen/grant-table: Refactor gnttab_[un]map_refs to avoid m2p_override
The grant mapping API does m2p_override unnecessarily: only gntdev needs it, for blkback and future netback patches it just cause a lock contention, as those pages never go to userspace. Therefore this series does the following: - the bulk of the original function (everything after the mapping hypercall) is moved to arch-dependent set/clear_foreign_p2m_mapping - the "if (xen_feature(XENFEAT_auto_translated_physmap))" branch goes to ARM - therefore the ARM function could be much smaller, the m2p_override stubs could be also removed - on x86 the set_phys_to_machine calls were moved up to this new funcion from m2p_override functions - and m2p_override functions are only called when there is a kmap_ops param It also removes a stray space from arch/x86/include/asm/xen/page.h. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Suggested-by: Anthony Liguori <aliguori@amazon.com> Suggested-by: David Vrabel <david.vrabel@citrix.com> Suggested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
This commit is contained in:
Zoltan Kiss
David Vrabel
parent
395edbb80b
commit
1429d46df4
@ -97,16 +97,13 @@ static inline pte_t *lookup_address(unsigned long address, unsigned int *level)
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return NULL;
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}
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static inline int m2p_add_override(unsigned long mfn, struct page *page,
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struct gnttab_map_grant_ref *kmap_op)
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{
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return 0;
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}
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extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count);
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static inline int m2p_remove_override(struct page *page, bool clear_pte)
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{
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return 0;
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}
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extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count);
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bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
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bool __set_phys_to_machine_multi(unsigned long pfn, unsigned long mfn,
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@ -146,6 +146,38 @@ unsigned long __mfn_to_pfn(unsigned long mfn)
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}
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EXPORT_SYMBOL_GPL(__mfn_to_pfn);
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int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count)
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{
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int i;
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for (i = 0; i < count; i++) {
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if (map_ops[i].status)
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continue;
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set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
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map_ops[i].dev_bus_addr >> PAGE_SHIFT);
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
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int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count)
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{
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int i;
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for (i = 0; i < count; i++) {
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set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
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INVALID_P2M_ENTRY);
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
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bool __set_phys_to_machine_multi(unsigned long pfn,
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unsigned long mfn, unsigned long nr_pages)
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{
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@ -49,10 +49,17 @@ extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
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extern unsigned long set_phys_range_identity(unsigned long pfn_s,
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unsigned long pfn_e);
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extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count);
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extern int m2p_add_override(unsigned long mfn, struct page *page,
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struct gnttab_map_grant_ref *kmap_op);
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extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count);
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extern int m2p_remove_override(struct page *page,
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struct gnttab_map_grant_ref *kmap_op);
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struct gnttab_map_grant_ref *kmap_op,
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unsigned long mfn);
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extern struct page *m2p_find_override(unsigned long mfn);
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extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
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@ -121,7 +128,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
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pfn = m2p_find_override_pfn(mfn, ~0);
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}
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/*
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/*
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* pfn is ~0 if there are no entries in the m2p for mfn or if the
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* entry doesn't map back to the mfn and m2p_override doesn't have a
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* valid entry for it.
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@ -881,6 +881,65 @@ static unsigned long mfn_hash(unsigned long mfn)
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return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT);
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}
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int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count)
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{
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int i, ret = 0;
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bool lazy = false;
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pte_t *pte;
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return 0;
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if (kmap_ops &&
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!in_interrupt() &&
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paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
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arch_enter_lazy_mmu_mode();
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lazy = true;
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}
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for (i = 0; i < count; i++) {
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unsigned long mfn, pfn;
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/* Do not add to override if the map failed. */
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if (map_ops[i].status)
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continue;
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if (map_ops[i].flags & GNTMAP_contains_pte) {
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pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
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(map_ops[i].host_addr & ~PAGE_MASK));
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mfn = pte_mfn(*pte);
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} else {
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mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
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}
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pfn = page_to_pfn(pages[i]);
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WARN_ON(PagePrivate(pages[i]));
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SetPagePrivate(pages[i]);
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set_page_private(pages[i], mfn);
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pages[i]->index = pfn_to_mfn(pfn);
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if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
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ret = -ENOMEM;
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goto out;
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}
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if (kmap_ops) {
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ret = m2p_add_override(mfn, pages[i], &kmap_ops[i]);
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if (ret)
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goto out;
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}
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}
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out:
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if (lazy)
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arch_leave_lazy_mmu_mode();
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return ret;
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}
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EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
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/* Add an MFN override for a particular page */
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int m2p_add_override(unsigned long mfn, struct page *page,
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struct gnttab_map_grant_ref *kmap_op)
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@ -899,13 +958,6 @@ int m2p_add_override(unsigned long mfn, struct page *page,
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"m2p_add_override: pfn %lx not mapped", pfn))
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return -EINVAL;
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}
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WARN_ON(PagePrivate(page));
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SetPagePrivate(page);
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set_page_private(page, mfn);
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page->index = pfn_to_mfn(pfn);
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if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
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return -ENOMEM;
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if (kmap_op != NULL) {
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if (!PageHighMem(page)) {
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@ -943,20 +995,62 @@ int m2p_add_override(unsigned long mfn, struct page *page,
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return 0;
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}
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EXPORT_SYMBOL_GPL(m2p_add_override);
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int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count)
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{
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int i, ret = 0;
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bool lazy = false;
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return 0;
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if (kmap_ops &&
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!in_interrupt() &&
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paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
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arch_enter_lazy_mmu_mode();
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lazy = true;
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}
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for (i = 0; i < count; i++) {
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unsigned long mfn = get_phys_to_machine(page_to_pfn(pages[i]));
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unsigned long pfn = page_to_pfn(pages[i]);
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if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
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ret = -EINVAL;
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goto out;
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}
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set_page_private(pages[i], INVALID_P2M_ENTRY);
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WARN_ON(!PagePrivate(pages[i]));
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ClearPagePrivate(pages[i]);
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set_phys_to_machine(pfn, pages[i]->index);
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if (kmap_ops)
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ret = m2p_remove_override(pages[i], &kmap_ops[i], mfn);
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if (ret)
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goto out;
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}
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out:
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if (lazy)
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arch_leave_lazy_mmu_mode();
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return ret;
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}
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EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
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int m2p_remove_override(struct page *page,
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struct gnttab_map_grant_ref *kmap_op)
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struct gnttab_map_grant_ref *kmap_op,
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unsigned long mfn)
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{
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unsigned long flags;
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unsigned long mfn;
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unsigned long pfn;
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unsigned long uninitialized_var(address);
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unsigned level;
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pte_t *ptep = NULL;
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pfn = page_to_pfn(page);
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mfn = get_phys_to_machine(pfn);
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if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
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return -EINVAL;
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if (!PageHighMem(page)) {
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address = (unsigned long)__va(pfn << PAGE_SHIFT);
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@ -970,10 +1064,7 @@ int m2p_remove_override(struct page *page,
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spin_lock_irqsave(&m2p_override_lock, flags);
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list_del(&page->lru);
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spin_unlock_irqrestore(&m2p_override_lock, flags);
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WARN_ON(!PagePrivate(page));
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ClearPagePrivate(page);
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set_phys_to_machine(pfn, page->index);
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if (kmap_op != NULL) {
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if (!PageHighMem(page)) {
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struct multicall_space mcs;
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@ -933,9 +933,6 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
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struct page **pages, unsigned int count)
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{
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int i, ret;
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bool lazy = false;
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pte_t *pte;
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unsigned long mfn;
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ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
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if (ret)
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@ -947,45 +944,7 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
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gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
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&map_ops[i].status, __func__);
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/* this is basically a nop on x86 */
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if (xen_feature(XENFEAT_auto_translated_physmap)) {
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for (i = 0; i < count; i++) {
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if (map_ops[i].status)
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continue;
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set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
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map_ops[i].dev_bus_addr >> PAGE_SHIFT);
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}
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return ret;
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}
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if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
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arch_enter_lazy_mmu_mode();
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lazy = true;
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}
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for (i = 0; i < count; i++) {
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/* Do not add to override if the map failed. */
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if (map_ops[i].status)
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continue;
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if (map_ops[i].flags & GNTMAP_contains_pte) {
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pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
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(map_ops[i].host_addr & ~PAGE_MASK));
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mfn = pte_mfn(*pte);
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} else {
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mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
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}
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ret = m2p_add_override(mfn, pages[i], kmap_ops ?
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&kmap_ops[i] : NULL);
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if (ret)
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goto out;
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}
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out:
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if (lazy)
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arch_leave_lazy_mmu_mode();
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return ret;
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return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
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}
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EXPORT_SYMBOL_GPL(gnttab_map_refs);
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@ -993,39 +952,13 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
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struct gnttab_map_grant_ref *kmap_ops,
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struct page **pages, unsigned int count)
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{
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int i, ret;
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bool lazy = false;
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int ret;
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ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
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if (ret)
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return ret;
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/* this is basically a nop on x86 */
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if (xen_feature(XENFEAT_auto_translated_physmap)) {
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for (i = 0; i < count; i++) {
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set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
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INVALID_P2M_ENTRY);
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}
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return ret;
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}
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if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
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arch_enter_lazy_mmu_mode();
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lazy = true;
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}
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for (i = 0; i < count; i++) {
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ret = m2p_remove_override(pages[i], kmap_ops ?
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&kmap_ops[i] : NULL);
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if (ret)
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goto out;
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}
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out:
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if (lazy)
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arch_leave_lazy_mmu_mode();
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return ret;
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return clear_foreign_p2m_mapping(unmap_ops, kmap_ops, pages, count);
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}
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EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
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