Konrad Rzeszutek Wilk
2013-Dec-13 02:10 UTC
[PATCH V10 12/14] xen/pvh: Use ballooning to allocate grant table pages [v2]
From: Mukesh Rathor <mukesh.rathor@oracle.com>
This patch fixes a fixme in Linux to use alloc_xenballooned_pages() to
allocate pfns for grant table pages instead of kmalloc. This also
simplifies add to physmap on the xen side a bit.
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v1: Rebase on xen/grant-table: correctly initialize grant table version 1]
Conflicts:
drivers/xen/grant-table.c
[v2: Rebase on xen: Convert printks to pr_<level>]
---
drivers/xen/grant-table.c | 67 +++++++++++++++++++++++++++++++++++---------
1 files changed, 53 insertions(+), 14 deletions(-)
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 1fcf75b..4467d54 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -50,6 +50,7 @@
#include <xen/interface/memory.h>
#include <xen/hvc-console.h>
#include <xen/swiotlb-xen.h>
+#include <xen/balloon.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>
@@ -1053,10 +1054,22 @@ static void gnttab_unmap_frames_v2(void)
arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
}
+static xen_pfn_t pvh_get_grant_pfn(int grant_idx)
+{
+ unsigned long vaddr;
+ unsigned int level;
+ pte_t *pte;
+
+ vaddr = (unsigned long)(gnttab_shared.addr) + grant_idx * PAGE_SIZE;
+ pte = lookup_address(vaddr, &level);
+ BUG_ON(pte == NULL);
+ return pte_mfn(*pte);
+}
+
static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
{
struct gnttab_setup_table setup;
- unsigned long start_gpfn;
+ unsigned long start_gpfn = 0;
xen_pfn_t *frames;
unsigned int nr_gframes = end_idx + 1;
int rc;
@@ -1068,8 +1081,6 @@ static int gnttab_map(unsigned int start_idx, unsigned int
end_idx)
if (xen_hvm_domain())
start_gpfn = xen_hvm_resume_frames >> PAGE_SHIFT;
- else
- start_gpfn = virt_to_pfn(gnttab_shared.addr);
/*
* Loop backwards, so that the first hypercall has the largest
* index, ensuring that the table will grow only once.
@@ -1078,7 +1089,11 @@ static int gnttab_map(unsigned int start_idx, unsigned
int end_idx)
xatp.domid = DOMID_SELF;
xatp.idx = i;
xatp.space = XENMAPSPACE_grant_table;
- xatp.gpfn = start_gpfn + i;
+ if (xen_hvm_domain())
+ xatp.gpfn = start_gpfn + i;
+ else
+ xatp.gpfn = pvh_get_grant_pfn(i);
+
rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
if (rc != 0) {
pr_warn("grant table add_to_physmap failed, err=%d\n",
@@ -1167,26 +1182,50 @@ static void gnttab_request_version(void)
pr_info("Grant tables using version %d layout\n",
grant_table_version);
}
+/*
+ * PVH: we need three things: virtual address, pfns, and mfns. The pfns
+ * are allocated via ballooning, then we call arch_gnttab_map_shared to
+ * allocate the VA and put pfn''s in the pte''s for the VA. The
mfn''s are
+ * finally allocated in gnttab_map() by xen which also populates the P2M.
+ */
+static int xlated_setup_gnttab_pages(unsigned long numpages, void **addr)
+{
+ int i, rc;
+ unsigned long pfns[numpages];
+ struct page *pages[numpages];
+
+ rc = alloc_xenballooned_pages(numpages, pages, 0);
+ if (rc != 0) {
+ pr_warn("%s Couldn''t balloon alloc %ld pfns rc:%d\n",
__func__,
+ numpages, rc);
+ return rc;
+ }
+ for (i = 0; i < numpages; i++)
+ pfns[i] = page_to_pfn(pages[i]);
+
+ rc = arch_gnttab_map_shared(pfns, numpages, numpages, addr);
+ if (rc != 0)
+ free_xenballooned_pages(numpages, pages);
+
+ return rc;
+}
+
static int gnttab_setup(void)
{
+ int rc;
unsigned int max_nr_gframes;
- char *kmsg = "Failed to kmalloc pages for pv in hvm grant frames\n";
max_nr_gframes = gnttab_max_grant_frames();
if (max_nr_gframes < nr_grant_frames)
return -ENOSYS;
- /* PVH note: xen will free existing kmalloc''d mfn in
- * XENMEM_add_to_physmap. TBD/FIXME: use xen ballooning instead of
- * kmalloc(). */
if (xen_pv_domain() && xen_feature(XENFEAT_auto_translated_physmap)
&&
!gnttab_shared.addr) {
- gnttab_shared.addr - kmalloc(max_nr_gframes * PAGE_SIZE, GFP_KERNEL);
- if (!gnttab_shared.addr) {
- pr_warn("%s", kmsg);
- return -ENOMEM;
- }
+
+ rc = xlated_setup_gnttab_pages((unsigned long)max_nr_gframes,
+ &gnttab_shared.addr);
+ if (rc != 0)
+ return rc;
}
if (xen_pv_domain())
return gnttab_map(0, nr_grant_frames - 1);
--
1.7.7.6