Date: Mon, 17 Aug 2015 18:42:46 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r286855 - head/sys/amd64/amd64 Message-ID: <201508171842.t7HIgkgD076691@repo.freebsd.org>
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Author: kib Date: Mon Aug 17 18:42:45 2015 New Revision: 286855 URL: https://svnweb.freebsd.org/changeset/base/286855 Log: XEN/amd64 may initiate i/o over the pages not mapped by the direct map. Handle busdma bouncing and ata PIO accesses by using global frame used by the current CPU locally for the duration of pmap_quick_enter/remove_page(). A spin mutex protects the concurent frame use and prevents thread migration. Noted by: royger Reviewed by: alc, jah, royger (previous version) Sponsored by: The FreeBSD Foundation Modified: head/sys/amd64/amd64/pmap.c Modified: head/sys/amd64/amd64/pmap.c ============================================================================== --- head/sys/amd64/amd64/pmap.c Mon Aug 17 18:36:16 2015 (r286854) +++ head/sys/amd64/amd64/pmap.c Mon Aug 17 18:42:45 2015 (r286855) @@ -390,6 +390,8 @@ static struct md_page *pv_table; */ pt_entry_t *CMAP1 = 0; caddr_t CADDR1 = 0; +static vm_offset_t qframe = 0; +static struct mtx qframe_mtx; static int pmap_flags = PMAP_PDE_SUPERPAGE; /* flags for x86 pmaps */ @@ -1031,7 +1033,7 @@ pmap_init(void) struct pmap_preinit_mapping *ppim; vm_page_t mpte; vm_size_t s; - int i, pv_npg; + int error, i, pv_npg; /* * Initialize the vm page array entries for the kernel pmap's @@ -1112,6 +1114,12 @@ pmap_init(void) printf("PPIM %u: PA=%#lx, VA=%#lx, size=%#lx, mode=%#x\n", i, ppim->pa, ppim->va, ppim->sz, ppim->mode); } + + mtx_init(&qframe_mtx, "qfrmlk", NULL, MTX_SPIN); + error = vmem_alloc(kernel_arena, PAGE_SIZE, M_BESTFIT | M_WAITOK, + (vmem_addr_t *)&qframe); + if (error != 0) + panic("qframe allocation failed"); } static SYSCTL_NODE(_vm_pmap, OID_AUTO, pde, CTLFLAG_RD, 0, @@ -7019,13 +7027,27 @@ pmap_unmap_io_transient(vm_page_t page[] vm_offset_t pmap_quick_enter_page(vm_page_t m) { + vm_paddr_t paddr; - return (PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m))); + paddr = VM_PAGE_TO_PHYS(m); + if (paddr < dmaplimit) + return (PHYS_TO_DMAP(paddr)); + mtx_lock_spin(&qframe_mtx); + KASSERT(*vtopte(qframe) == 0, ("qframe busy")); + pte_store(vtopte(qframe), paddr | X86_PG_RW | X86_PG_V | X86_PG_A | + X86_PG_M | pmap_cache_bits(kernel_pmap, m->md.pat_mode, 0)); + return (qframe); } void pmap_quick_remove_page(vm_offset_t addr) { + + if (addr != qframe) + return; + pte_store(vtopte(qframe), 0); + invlpg(qframe); + mtx_unlock_spin(&qframe_mtx); } #include "opt_ddb.h"
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