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Date:      Sat, 29 Sep 2012 01:15:45 +0000 (UTC)
From:      Neel Natu <neel@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-projects@freebsd.org
Subject:   svn commit: r241041 - in projects/bhyve/sys/amd64: include vmm
Message-ID:  <201209290115.q8T1Fjv3037688@svn.freebsd.org>
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Author: neel
Date: Sat Sep 29 01:15:45 2012
New Revision: 241041
URL: http://svn.freebsd.org/changeset/base/241041

Log:
  Get rid of assumptions in the hypervisor that the host physical memory
  associated with guest physical memory is contiguous.
  
  In this case vm_malloc() was using vm_gpa2hpa() to indirectly infer whether
  or not the address range had already been allocated.
  
  Replace this instead with an explicit API 'vm_gpa_available()' that returns
  TRUE if a page is available for allocation in guest physical address space.

Modified:
  projects/bhyve/sys/amd64/include/vmm.h
  projects/bhyve/sys/amd64/vmm/vmm.c
  projects/bhyve/sys/amd64/vmm/vmm_dev.c

Modified: projects/bhyve/sys/amd64/include/vmm.h
==============================================================================
--- projects/bhyve/sys/amd64/include/vmm.h	Fri Sep 28 22:26:44 2012	(r241040)
+++ projects/bhyve/sys/amd64/include/vmm.h	Sat Sep 29 01:15:45 2012	(r241041)
@@ -89,7 +89,7 @@ extern struct vmm_ops vmm_ops_amd;
 struct vm *vm_create(const char *name);
 void vm_destroy(struct vm *vm);
 const char *vm_name(struct vm *vm);
-int vm_malloc(struct vm *vm, vm_paddr_t gpa, size_t len, vm_paddr_t *ret_hpa);
+int vm_malloc(struct vm *vm, vm_paddr_t gpa, size_t len);
 int vm_map_mmio(struct vm *vm, vm_paddr_t gpa, size_t len, vm_paddr_t hpa);
 int vm_unmap_mmio(struct vm *vm, vm_paddr_t gpa, size_t len);
 vm_paddr_t vm_gpa2hpa(struct vm *vm, vm_paddr_t gpa, size_t size);

Modified: projects/bhyve/sys/amd64/vmm/vmm.c
==============================================================================
--- projects/bhyve/sys/amd64/vmm/vmm.c	Fri Sep 28 22:26:44 2012	(r241040)
+++ projects/bhyve/sys/amd64/vmm/vmm.c	Sat Sep 29 01:15:45 2012	(r241041)
@@ -315,20 +315,63 @@ vm_unmap_mmio(struct vm *vm, vm_paddr_t 
 		       VM_PROT_NONE, spok));
 }
 
+/*
+ * Returns TRUE if 'gpa' is available for allocation and FALSE otherwise
+ */
+static boolean_t
+vm_gpa_available(struct vm *vm, vm_paddr_t gpa)
+{
+	int i;
+	vm_paddr_t gpabase, gpalimit;
+
+	if (gpa & PAGE_MASK)
+		panic("vm_gpa_available: gpa (0x%016lx) not page aligned", gpa);
+
+	for (i = 0; i < vm->num_mem_segs; i++) {
+		gpabase = vm->mem_segs[i].gpa;
+		gpalimit = gpabase + vm->mem_segs[i].len;
+		if (gpa >= gpabase && gpa < gpalimit)
+			return (FALSE);
+	}
+
+	return (TRUE);
+}
+
 int
-vm_malloc(struct vm *vm, vm_paddr_t gpa, size_t len, vm_paddr_t *ret_hpa)
+vm_malloc(struct vm *vm, vm_paddr_t gpa, size_t len)
 {
-	int error;
-	vm_paddr_t hpa;
+	int error, available, allocated;
+	vm_paddr_t g, hpa;
 
 	const boolean_t spok = TRUE;	/* superpage mappings are ok */
+
+	if ((gpa & PAGE_MASK) || (len & PAGE_MASK) || len == 0)
+		return (EINVAL);
 	
+	available = allocated = 0;
+	g = gpa;
+	while (g < gpa + len) {
+		if (vm_gpa_available(vm, g))
+			available++;
+		else
+			allocated++;
+
+		g += PAGE_SIZE;
+	}
+
 	/*
-	 * find the hpa if already it was already vm_malloc'd.
+	 * If there are some allocated and some available pages in the address
+	 * range then it is an error.
 	 */
-	hpa = vm_gpa2hpa(vm, gpa, len);
-	if (hpa != ((vm_paddr_t)-1))
-		goto out;
+	if (allocated && available)
+		return (EINVAL);
+
+	/*
+	 * If the entire address range being requested has already been
+	 * allocated then there isn't anything more to do.
+	 */
+	if (allocated && available == 0)
+		return (0);
 
 	if (vm->num_mem_segs >= VM_MAX_MEMORY_SEGMENTS)
 		return (E2BIG);
@@ -350,8 +393,7 @@ vm_malloc(struct vm *vm, vm_paddr_t gpa,
 	vm->mem_segs[vm->num_mem_segs].hpa = hpa;
 	vm->mem_segs[vm->num_mem_segs].len = len;
 	vm->num_mem_segs++;
-out:
-	*ret_hpa = hpa;
+
 	return (0);
 }
 

Modified: projects/bhyve/sys/amd64/vmm/vmm_dev.c
==============================================================================
--- projects/bhyve/sys/amd64/vmm/vmm_dev.c	Fri Sep 28 22:26:44 2012	(r241040)
+++ projects/bhyve/sys/amd64/vmm/vmm_dev.c	Sat Sep 29 01:15:45 2012	(r241041)
@@ -295,7 +295,7 @@ vmmdev_ioctl(struct cdev *cdev, u_long c
 		break;
 	case VM_MAP_MEMORY:
 		seg = (struct vm_memory_segment *)data;
-		error = vm_malloc(sc->vm, seg->gpa, seg->len, &seg->hpa);
+		error = vm_malloc(sc->vm, seg->gpa, seg->len);
 		break;
 	case VM_GET_MEMORY_SEG:
 		seg = (struct vm_memory_segment *)data;

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