Attachment 288731 Details for Bug 249867 – xen-unstable 10361:2ac74e1df3d7 ported to 2.6.9-67.EL

[patch] xen-unstable 10361:2ac74e1df3d7 ported to 2.6.9-67.EL

xen-unstable-10361-2ac74e1df3d7 (text/plain), 8.44 KB, created by Ian Campbell on 2007-12-14 08:58:19 UTC

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Creator: Ian Campbell

Created: 2007-12-14 08:58:19 UTC

Size: 8.44 KB

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obsolete

># HG changeset patch
># User kfraser@dhcp93.uk.xensource.com
># Node ID 2ac74e1df3d7d7751a128d2ad2fe9cc3a9d23c54
># Parent  ee3d108289370351347f46284024f3347897d2bb
>[LINUX] Use new XENMEM_exchange hypercall (where possible)
>to provide watertight implementations that should never crash
>in ENOMEM situations.
>Signed-off-by: Keir Fraser <keir@xensource.com>
>xen-unstable changeset: 10361:2ac74e1df3d7d7751a128d2ad2fe9cc3a9d23c54
>xen-unstable date: Fri Jun 16 14:45:01 2006 +0100
>
>Index: linux-2.6.9-67.EL/arch/i386/mm/hypervisor.c
>===================================================================
>--- linux-2.6.9-67.EL.orig/arch/i386/mm/hypervisor.c	2007-11-29 16:05:41.000000000 +0000
>+++ linux-2.6.9-67.EL/arch/i386/mm/hypervisor.c	2007-11-29 16:06:53.000000000 +0000
>@@ -261,6 +261,10 @@
> 	}
> }
> 
>+/* Protected by balloon_lock. */
>+#define MAX_CONTIG_ORDER 7
>+static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
>+
> /* Ensure multi-page extents are contiguous in machine memory. */
> int xen_create_contiguous_region(
> 	unsigned long vstart, unsigned int order, unsigned int address_bits)
>@@ -268,13 +272,23 @@
> 	pgd_t         *pgd; 
> 	pmd_t         *pmd;
> 	pte_t         *pte;
>+	unsigned long *in_frames = discontig_frames, out_frame;
> 	unsigned long  frame, i, flags;
>-	struct xen_memory_reservation reservation = {
>-		.nr_extents   = 1,
>-		.extent_order = 0,
>-		.domid        = DOMID_SELF
>+	long           rc;
>+	int            success;
>+	struct xen_memory_exchange exchange = {
>+		.in = {
>+			.nr_extents   = 1UL << order,
>+			.extent_order = 0,
>+			.domid        = DOMID_SELF
>+		},
>+		.out = {
>+			.nr_extents   = 1,
>+			.extent_order = order,
>+			.address_bits = address_bits,
>+			.domid        = DOMID_SELF
>+		}
> 	};
>-	set_xen_guest_handle(reservation.extent_start, &frame);
> 
> 	/*
> 	 * Currently an auto-translated guest will not perform I/O, nor will
>@@ -284,67 +298,72 @@
> 	if (xen_feature(XENFEAT_auto_translated_physmap))
> 		return 0;
> 
>+	if (order > MAX_CONTIG_ORDER)
>+		return -ENOMEM;
>+
>+	set_xen_guest_handle(exchange.in.extent_start, in_frames);
>+	set_xen_guest_handle(exchange.out.extent_start, &out_frame);
>+
> 	scrub_pages(vstart, 1 << order);
> 
> 	balloon_lock(flags);
> 
>-	/* 1. Zap current PTEs, giving away the underlying pages. */
>-	for (i = 0; i < (1<<order); i++) {
>+	/* 1. Zap current PTEs, remembering MFNs. */
>+	for (i = 0; i < (1UL<<order); i++) {
> 		pgd = pgd_offset_k(vstart + (i*PAGE_SIZE));
> 		pmd = pmd_offset(pgd, (vstart + (i*PAGE_SIZE)));
> 		pte = pte_offset_kernel(pmd, (vstart + (i*PAGE_SIZE)));
>-		frame = pte_mfn(*pte);
>-		BUG_ON(HYPERVISOR_update_va_mapping(
>-			vstart + (i*PAGE_SIZE), __pte_ma(0), 0));
>+		in_frames[i] = pte_mfn(*pte);
>+		if (HYPERVISOR_update_va_mapping(vstart + (i*PAGE_SIZE),
>+						 __pte_ma(0), 0))
>+			BUG();
> 		set_phys_to_machine((__pa(vstart)>>PAGE_SHIFT)+i,
> 			INVALID_P2M_ENTRY);
>-		BUG_ON(HYPERVISOR_memory_op(
>-			XENMEM_decrease_reservation, &reservation) != 1);
> 	}
> 
> 	/* 2. Get a new contiguous memory extent. */
>-	reservation.extent_order = order;
>-	reservation.address_bits = address_bits;
>-	frame = __pa(vstart) >> PAGE_SHIFT;
>-	if (HYPERVISOR_memory_op(XENMEM_populate_physmap,
>-				 &reservation) != 1)
>-		goto fail;
>-
>-	/* 3. Map the new extent in place of old pages. */
>-	for (i = 0; i < (1<<order); i++) {
>-		BUG_ON(HYPERVISOR_update_va_mapping(
>-			vstart + (i*PAGE_SIZE),
>-			pfn_pte_ma(frame+i, PAGE_KERNEL), 0));
>-		set_phys_to_machine((__pa(vstart)>>PAGE_SHIFT)+i, frame+i);
>+	out_frame = __pa(vstart) >> PAGE_SHIFT;
>+	rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
>+	success = (exchange.nr_exchanged == (1UL << order));
>+	BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
>+	BUG_ON(success && (rc != 0));
>+	if (unlikely(rc == -ENOSYS)) {
>+		/* Compatibility when XENMEM_exchange is unsupported. */
>+		if (HYPERVISOR_memory_op(XENMEM_decrease_reservation,
>+					 &exchange.in) != (1UL << order))
>+			BUG();
>+		success = (HYPERVISOR_memory_op(XENMEM_populate_physmap,
>+						&exchange.out) == 1);
>+		if (!success) {
>+			/* Couldn't get special memory: fall back to normal. */
>+			for (i = 0; i < (1UL<<order); i++)
>+				in_frames[i] = (__pa(vstart)>>PAGE_SHIFT) + i;
>+			if (HYPERVISOR_memory_op(XENMEM_populate_physmap,
>+						 &exchange.in) != (1UL<<order))
>+				BUG();
>+		}
> 	}
> 
>-	flush_tlb_all();
>-
>-	contiguous_bitmap_set(__pa(vstart) >> PAGE_SHIFT, 1UL << order);
>-
>-	balloon_unlock(flags);
>-
>-	return 0;
>-
>- fail:
>-	reservation.extent_order = 0;
>-	reservation.address_bits = 0;
>-
>-	for (i = 0; i < (1<<order); i++) {
>-		frame = (__pa(vstart) >> PAGE_SHIFT) + i;
>-		BUG_ON(HYPERVISOR_memory_op(
>-			XENMEM_populate_physmap, &reservation) != 1);
>-		BUG_ON(HYPERVISOR_update_va_mapping(
>-			vstart + (i*PAGE_SIZE),
>-			pfn_pte_ma(frame, PAGE_KERNEL), 0));
>+	/* 3. Map the new extent in place of old pages. */
>+	for (i = 0; i < (1UL<<order); i++) {
>+		frame = success ? (out_frame + i) : in_frames[i];
>+		if (HYPERVISOR_update_va_mapping(vstart + (i*PAGE_SIZE),
>+						 pfn_pte_ma(frame,
>+							    PAGE_KERNEL),
>+						 0))
>+			BUG();
> 		set_phys_to_machine((__pa(vstart)>>PAGE_SHIFT)+i, frame);
> 	}
> 
> 	flush_tlb_all();
> 
>+	if (success)
>+		contiguous_bitmap_set(__pa(vstart) >> PAGE_SHIFT,
>+				      1UL << order);
>+
> 	balloon_unlock(flags);
> 
>-	return -ENOMEM;
>+	return success ? 0 : -ENOMEM;
> }
> 
> void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
>@@ -352,46 +371,78 @@
> 	pgd_t         *pgd; 
> 	pmd_t         *pmd;
> 	pte_t         *pte;
>+	unsigned long *out_frames = discontig_frames, in_frame;
> 	unsigned long  frame, i, flags;
>-	struct xen_memory_reservation reservation = {
>-		.nr_extents   = 1,
>-		.extent_order = 0,
>-		.domid        = DOMID_SELF
>+	long           rc;
>+	int            success;
>+	struct xen_memory_exchange exchange = {
>+		.in = {
>+			.nr_extents   = 1,
>+			.extent_order = order,
>+			.domid        = DOMID_SELF
>+		},
>+		.out = {
>+			.nr_extents   = 1UL << order,
>+			.extent_order = 0,
>+			.domid        = DOMID_SELF
>+		}
> 	};
>-	set_xen_guest_handle(reservation.extent_start, &frame);
> 
> 	if (xen_feature(XENFEAT_auto_translated_physmap) ||
> 	    !test_bit(__pa(vstart) >> PAGE_SHIFT, contiguous_bitmap))
> 		return;
> 
>+	if (order > MAX_CONTIG_ORDER)
>+		return;
>+
>+	set_xen_guest_handle(exchange.in.extent_start, &in_frame);
>+	set_xen_guest_handle(exchange.out.extent_start, out_frames);
>+
> 	scrub_pages(vstart, 1 << order);
> 
> 	balloon_lock(flags);
> 
> 	contiguous_bitmap_clear(__pa(vstart) >> PAGE_SHIFT, 1UL << order);
> 
>-	/* 1. Zap current PTEs, giving away the underlying pages. */
>-	for (i = 0; i < (1<<order); i++) {
>-		pgd = pgd_offset_k(vstart + (i*PAGE_SIZE));
>-		pmd = pmd_offset(pgd, (vstart + (i*PAGE_SIZE)));
>-		pte = pte_offset_kernel(pmd, (vstart + (i*PAGE_SIZE)));
>-		frame = pte_mfn(*pte);
>-		BUG_ON(HYPERVISOR_update_va_mapping(
>-			vstart + (i*PAGE_SIZE), __pte_ma(0), 0));
>+	/* 1. Find start MFN of contiguous extent. */
>+	pgd = pgd_offset_k(vstart);
>+	pmd = pmd_offset(pgd, vstart);
>+	pte = pte_offset_kernel(pmd, vstart);
>+	in_frame = pte_mfn(*pte);
>+
>+	/* 2. Zap current PTEs. */
>+	for (i = 0; i < (1UL<<order); i++) {
>+		if (HYPERVISOR_update_va_mapping(vstart + (i*PAGE_SIZE),
>+						 __pte_ma(0), 0));
> 		set_phys_to_machine((__pa(vstart)>>PAGE_SHIFT)+i,
> 			INVALID_P2M_ENTRY);
>-		BUG_ON(HYPERVISOR_memory_op(
>-			XENMEM_decrease_reservation, &reservation) != 1);
>+		out_frames[i] = (__pa(vstart) >> PAGE_SHIFT) + i;
> 	}
> 
>-	/* 2. Map new pages in place of old pages. */
>-	for (i = 0; i < (1<<order); i++) {
>-		frame = (__pa(vstart) >> PAGE_SHIFT) + i;
>-		BUG_ON(HYPERVISOR_memory_op(
>-			XENMEM_populate_physmap, &reservation) != 1);
>-		BUG_ON(HYPERVISOR_update_va_mapping(
>-			vstart + (i*PAGE_SIZE),
>-			pfn_pte_ma(frame, PAGE_KERNEL), 0));
>+	/* 3. Do the exchange for non-contiguous MFNs. */
>+	rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
>+	success = (exchange.nr_exchanged == 1);
>+	BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
>+	BUG_ON(success && (rc != 0));
>+	if (rc == -ENOSYS) {
>+		/* Compatibility when XENMEM_exchange is unsupported. */
>+		if (HYPERVISOR_memory_op(XENMEM_decrease_reservation,
>+					 &exchange.in) != 1)
>+			BUG();
>+		if (HYPERVISOR_memory_op(XENMEM_populate_physmap,
>+					 &exchange.out) != (1UL << order))
>+			BUG();
>+		success = 1;
>+	}
>+
>+	/* 4. Map new pages in place of old pages. */
>+	for (i = 0; i < (1UL<<order); i++) {
>+		frame = success ? out_frames[i] : (in_frame + i);
>+		if (HYPERVISOR_update_va_mapping(vstart + (i*PAGE_SIZE),
>+						 pfn_pte_ma(frame,
>+							    PAGE_KERNEL),
>+						 0))
>+			BUG();
> 		set_phys_to_machine((__pa(vstart)>>PAGE_SHIFT)+i, frame);
> 	}
>

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Attachments on bug 249867: 288721 | 288731 | 295742 | 295745 | 328115