From 0aad5689837c882d2539f50f42f686b74046c0a0 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 28 Nov 2014 11:53:57 +0100 Subject: [PATCH] xen: Hide get_phys_to_machine() to be able to tune common path Today get_phys_to_machine() is always called when the mfn for a pfn is to be obtained. Add a wrapper __pfn_to_mfn() as inline function to be able to avoid calling get_phys_to_machine() when possible as soon as the switch to a linear mapped p2m list has been done. Signed-off-by: Juergen Gross Reviewed-by: David Vrabel Signed-off-by: David Vrabel --- arch/x86/include/asm/xen/page.h | 26 ++++++++++++++++++++------ arch/x86/xen/mmu.c | 2 +- arch/x86/xen/p2m.c | 6 +++--- 3 files changed, 24 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index a4a265fcab17..57aba6ba6f92 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -59,6 +59,21 @@ extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, struct page **pages, unsigned int count); extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn); +/* + * When to use pfn_to_mfn(), __pfn_to_mfn() or get_phys_to_machine(): + * - pfn_to_mfn() returns either INVALID_P2M_ENTRY or the mfn. No indicator + * bits (identity or foreign) are set. + * - __pfn_to_mfn() returns the found entry of the p2m table. A possibly set + * identity or foreign indicator will be still set. __pfn_to_mfn() is + * encapsulating get_phys_to_machine(). + * - get_phys_to_machine() is to be called by __pfn_to_mfn() only to allow + * for future optimizations. + */ +static inline unsigned long __pfn_to_mfn(unsigned long pfn) +{ + return get_phys_to_machine(pfn); +} + static inline unsigned long pfn_to_mfn(unsigned long pfn) { unsigned long mfn; @@ -66,7 +81,7 @@ static inline unsigned long pfn_to_mfn(unsigned long pfn) if (xen_feature(XENFEAT_auto_translated_physmap)) return pfn; - mfn = get_phys_to_machine(pfn); + mfn = __pfn_to_mfn(pfn); if (mfn != INVALID_P2M_ENTRY) mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT); @@ -79,7 +94,7 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn) if (xen_feature(XENFEAT_auto_translated_physmap)) return 1; - return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY; + return __pfn_to_mfn(pfn) != INVALID_P2M_ENTRY; } static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn) @@ -113,7 +128,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) return mfn; pfn = mfn_to_pfn_no_overrides(mfn); - if (get_phys_to_machine(pfn) != mfn) { + if (__pfn_to_mfn(pfn) != mfn) { /* * If this appears to be a foreign mfn (because the pfn * doesn't map back to the mfn), then check the local override @@ -129,8 +144,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) * entry doesn't map back to the mfn and m2p_override doesn't have a * valid entry for it. */ - if (pfn == ~0 && - get_phys_to_machine(mfn) == IDENTITY_FRAME(mfn)) + if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn)) pfn = mfn; return pfn; @@ -176,7 +190,7 @@ static inline unsigned long mfn_to_local_pfn(unsigned long mfn) return mfn; pfn = mfn_to_pfn(mfn); - if (get_phys_to_machine(pfn) != mfn) + if (__pfn_to_mfn(pfn) != mfn) return -1; /* force !pfn_valid() */ return pfn; } diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 601914d2b0a8..3e3f8f8c3a30 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -387,7 +387,7 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) unsigned long mfn; if (!xen_feature(XENFEAT_auto_translated_physmap)) - mfn = get_phys_to_machine(pfn); + mfn = __pfn_to_mfn(pfn); else mfn = pfn; /* diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index eddec40a4c20..8c3d8fbbba93 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -787,7 +787,7 @@ static int m2p_add_override(unsigned long mfn, struct page *page, * because mfn_to_pfn (that ends up being called by GUPF) will * return the backend pfn rather than the frontend pfn. */ pfn = mfn_to_pfn_no_overrides(mfn); - if (get_phys_to_machine(pfn) == mfn) + if (__pfn_to_mfn(pfn) == mfn) set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)); return 0; @@ -967,7 +967,7 @@ static int m2p_remove_override(struct page *page, * pfn again. */ mfn &= ~FOREIGN_FRAME_BIT; pfn = mfn_to_pfn_no_overrides(mfn); - if (get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) && + if (__pfn_to_mfn(pfn) == FOREIGN_FRAME(mfn) && m2p_find_override(mfn) == NULL) set_phys_to_machine(pfn, mfn); @@ -992,7 +992,7 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, } for (i = 0; i < count; i++) { - unsigned long mfn = get_phys_to_machine(page_to_pfn(pages[i])); + unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); unsigned long pfn = page_to_pfn(pages[i]); if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { -- 2.39.2