lkml.org 
[lkml]   [2013]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] PVH linux: Use ballooning to allocate grant table pages
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>

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 9c0019d..fdb1d88 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -47,6 +47,7 @@
#include <xen/grant_table.h>
#include <xen/interface/memory.h>
#include <xen/hvc-console.h>
+#include <xen/balloon.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>

@@ -1026,10 +1027,22 @@ 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 *frames, start_gpfn;
+ unsigned long *frames, start_gpfn = 0;
unsigned int nr_gframes = end_idx + 1;
int rc;

@@ -1040,8 +1053,6 @@ 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.
@@ -1050,7 +1061,11 @@ 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) {
printk(KERN_WARNING
@@ -1138,27 +1153,51 @@ static void gnttab_request_version(void)
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;
+}
+
int gnttab_resume(void)
{
+ int rc;
unsigned int max_nr_gframes;
- char *kmsg = "Failed to kmalloc pages for pv in hvm grant frames\n";

gnttab_request_version();
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);

\
 
 \ /
  Last update: 2013-02-06 00:43    [W:0.041 / U:2.360 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site