svn commit: r292906 - in stable/10/sys/dev: virtio/balloon xen/balloon
Roger Pau Monné
royger at FreeBSD.org
Wed Dec 30 08:15:45 UTC 2015
Author: royger
Date: Wed Dec 30 08:15:43 2015
New Revision: 292906
URL: https://svnweb.freebsd.org/changeset/base/292906
Log:
MFC r267858:
xen/virtio: fix balloon drivers to not mark pages as WIRED
In the Xen case make sure pages are zeroed before giving them back to the
hypervisor, or else we might be leaking data. Also remove the
balloon_{append/retrieve} and link pages directly into the ballooned_pages
queue using the plinks.q field in the page struct.
Sponsored by: Citrix Systems R&D
Requested by: bapt
Modified:
stable/10/sys/dev/virtio/balloon/virtio_balloon.c
stable/10/sys/dev/xen/balloon/balloon.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/dev/virtio/balloon/virtio_balloon.c
==============================================================================
--- stable/10/sys/dev/virtio/balloon/virtio_balloon.c Wed Dec 30 08:02:11 2015 (r292905)
+++ stable/10/sys/dev/virtio/balloon/virtio_balloon.c Wed Dec 30 08:15:43 2015 (r292906)
@@ -438,8 +438,7 @@ vtballoon_alloc_page(struct vtballoon_so
{
vm_page_t m;
- m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | VM_ALLOC_WIRED |
- VM_ALLOC_NOOBJ);
+ m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOOBJ);
if (m != NULL)
sc->vtballoon_current_npages++;
@@ -450,7 +449,6 @@ static void
vtballoon_free_page(struct vtballoon_softc *sc, vm_page_t m)
{
- vm_page_unwire(m, 0);
vm_page_free(m);
sc->vtballoon_current_npages--;
}
Modified: stable/10/sys/dev/xen/balloon/balloon.c
==============================================================================
--- stable/10/sys/dev/xen/balloon/balloon.c Wed Dec 30 08:02:11 2015 (r292905)
+++ stable/10/sys/dev/xen/balloon/balloon.c Wed Dec 30 08:15:43 2015 (r292906)
@@ -94,13 +94,8 @@ SYSCTL_ULONG(_dev_xen_balloon, OID_AUTO,
SYSCTL_ULONG(_dev_xen_balloon, OID_AUTO, high_mem, CTLFLAG_RD,
&bs.balloon_high, 0, "High-mem balloon");
-struct balloon_entry {
- vm_page_t page;
- STAILQ_ENTRY(balloon_entry) list;
-};
-
/* List of ballooned pages, threaded through the mem_map array. */
-static STAILQ_HEAD(,balloon_entry) ballooned_pages;
+static TAILQ_HEAD(,vm_page) ballooned_pages;
/* Main work function, always executed in process context. */
static void balloon_process(void *unused);
@@ -110,47 +105,6 @@ static void balloon_process(void *unused
#define WPRINTK(fmt, args...) \
printk(KERN_WARNING "xen_mem: " fmt, ##args)
-/* balloon_append: add the given page to the balloon. */
-static int
-balloon_append(vm_page_t page)
-{
- struct balloon_entry *entry;
-
- mtx_assert(&balloon_mutex, MA_OWNED);
-
- entry = malloc(sizeof(struct balloon_entry), M_BALLOON, M_NOWAIT);
- if (!entry)
- return (ENOMEM);
- entry->page = page;
- STAILQ_INSERT_HEAD(&ballooned_pages, entry, list);
- bs.balloon_low++;
-
- return (0);
-}
-
-/* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
-static vm_page_t
-balloon_retrieve(void)
-{
- vm_page_t page;
- struct balloon_entry *entry;
-
- mtx_assert(&balloon_mutex, MA_OWNED);
-
- if (STAILQ_EMPTY(&ballooned_pages))
- return (NULL);
-
- entry = STAILQ_FIRST(&ballooned_pages);
- STAILQ_REMOVE_HEAD(&ballooned_pages, list);
-
- page = entry->page;
- free(entry, M_BALLOON);
-
- bs.balloon_low--;
-
- return (page);
-}
-
static unsigned long
current_target(void)
{
@@ -203,7 +157,6 @@ static int
increase_reservation(unsigned long nr_pages)
{
unsigned long pfn, i;
- struct balloon_entry *entry;
vm_page_t page;
long rc;
struct xen_memory_reservation reservation = {
@@ -217,10 +170,9 @@ increase_reservation(unsigned long nr_pa
if (nr_pages > nitems(frame_list))
nr_pages = nitems(frame_list);
- for (entry = STAILQ_FIRST(&ballooned_pages), i = 0;
- i < nr_pages; i++, entry = STAILQ_NEXT(entry, list)) {
- KASSERT(entry, ("ballooned_pages list corrupt"));
- page = entry->page;
+ for (page = TAILQ_FIRST(&ballooned_pages), i = 0;
+ i < nr_pages; i++, page = TAILQ_NEXT(page, plinks.q)) {
+ KASSERT(page != NULL, ("ballooned_pages list corrupt"));
frame_list[i] = (VM_PAGE_TO_PHYS(page) >> PAGE_SHIFT);
}
@@ -245,8 +197,10 @@ increase_reservation(unsigned long nr_pa
}
for (i = 0; i < nr_pages; i++) {
- page = balloon_retrieve();
- KASSERT(page, ("balloon_retrieve failed"));
+ page = TAILQ_FIRST(&ballooned_pages);
+ KASSERT(page != NULL, ("Unable to get ballooned page"));
+ TAILQ_REMOVE(&ballooned_pages, page, plinks.q);
+ bs.balloon_low--;
pfn = (VM_PAGE_TO_PHYS(page) >> PAGE_SHIFT);
KASSERT((xen_feature(XENFEAT_auto_translated_physmap) ||
@@ -255,7 +209,6 @@ increase_reservation(unsigned long nr_pa
set_phys_to_machine(pfn, frame_list[i]);
- vm_page_unwire(page, 0);
vm_page_free(page);
}
@@ -286,24 +239,29 @@ decrease_reservation(unsigned long nr_pa
for (i = 0; i < nr_pages; i++) {
if ((page = vm_page_alloc(NULL, 0,
VM_ALLOC_NORMAL | VM_ALLOC_NOOBJ |
- VM_ALLOC_WIRED | VM_ALLOC_ZERO)) == NULL) {
+ VM_ALLOC_ZERO)) == NULL) {
nr_pages = i;
need_sleep = 1;
break;
}
+ if ((page->flags & PG_ZERO) == 0) {
+ /*
+ * Zero the page, or else we might be leaking
+ * important data to other domains on the same
+ * host. Xen doesn't scrub ballooned out memory
+ * pages, the guest is in charge of making
+ * sure that no information is leaked.
+ */
+ pmap_zero_page(page);
+ }
+
pfn = (VM_PAGE_TO_PHYS(page) >> PAGE_SHIFT);
frame_list[i] = PFNTOMFN(pfn);
set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
- if (balloon_append(page) != 0) {
- vm_page_unwire(page, 0);
- vm_page_free(page);
-
- nr_pages = i;
- need_sleep = 1;
- break;
- }
+ TAILQ_INSERT_HEAD(&ballooned_pages, page, plinks.q);
+ bs.balloon_low++;
}
set_xen_guest_handle(reservation.extent_start, frame_list);
@@ -438,7 +396,8 @@ balloon_init(void *arg)
/* Initialise the balloon with excess memory space. */
for (pfn = xen_start_info->nr_pages; pfn < max_pfn; pfn++) {
page = PHYS_TO_VM_PAGE(pfn << PAGE_SHIFT);
- balloon_append(page);
+ TAILQ_INSERT_HEAD(&ballooned_pages, page, plinks.q);
+ bs.balloon_low++;
}
#undef max_pfn
#endif
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