Date: Tue, 24 Sep 2013 18:46:18 +0000 (UTC) From: Neel Natu <neel@FreeBSD.org> To: src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: svn commit: r255858 - projects/bhyve_npt_pmap/sys/amd64/vmm Message-ID: <201309241846.r8OIkIwh071751@svn.freebsd.org>
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Author: neel Date: Tue Sep 24 18:46:18 2013 New Revision: 255858 URL: http://svnweb.freebsd.org/changeset/base/255858 Log: Use 'vm_fault_quick_hold_pages()' to hold pages belonging to the guest address space before accessing them in the host. We used to use 'vm_fault_hold()' prior to this change. This worked correctly but had the drawback that it would 'pmap_enter()' the gpa->hpa mapping unconditionally in the nested pmap. This in turn would cause unnecessary superpage demotions and promotions if the 'gpa' happened to be a superpage mapping. Discussed with: alc@, kib@ Modified: projects/bhyve_npt_pmap/sys/amd64/vmm/vmm.c Modified: projects/bhyve_npt_pmap/sys/amd64/vmm/vmm.c ============================================================================== --- projects/bhyve_npt_pmap/sys/amd64/vmm/vmm.c Tue Sep 24 18:24:01 2013 (r255857) +++ projects/bhyve_npt_pmap/sys/amd64/vmm/vmm.c Tue Sep 24 18:46:18 2013 (r255858) @@ -602,17 +602,17 @@ void * vm_gpa_hold(struct vm *vm, vm_paddr_t gpa, size_t len, int reqprot, void **cookie) { - int rv, pageoff; + int count, pageoff; vm_page_t m; pageoff = gpa & PAGE_MASK; if (len > PAGE_SIZE - pageoff) panic("vm_gpa_hold: invalid gpa/len: 0x%016lx/%lu", gpa, len); - rv = vm_fault_hold(&vm->vmspace->vm_map, trunc_page(gpa), reqprot, - VM_FAULT_NORMAL, &m); + count = vm_fault_quick_hold_pages(&vm->vmspace->vm_map, + trunc_page(gpa), PAGE_SIZE, reqprot, &m, 1); - if (rv == KERN_SUCCESS) { + if (count == 1) { *cookie = m; return ((void *)(PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m)) + pageoff)); } else {help
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