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Date: Thu, 14 May 2015 18:01:02 +0100
From: Julien Grall <julien.grall@...rix.com>
To: <xen-devel@...ts.xenproject.org>
CC: <linux-arm-kernel@...ts.infradead.org>, <ian.campbell@...rix.com>,
<stefano.stabellini@...citrix.com>, <linux-kernel@...r.kernel.org>,
<tim@....org>, Julien Grall <julien.grall@...rix.com>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
"David Vrabel" <david.vrabel@...rix.com>
Subject: [RFC 22/23] xen/privcmd: Add support for Linux 64KB page granularity
The hypercall interface (as well as the toolstack) is always using 4KB
page granularity. When the toolstack is asking for mapping a series of
guest PFN in a batch, it expects to have the page map contiguously in
its virtual memory.
When Linux is using 64KB page granularity, the privcmd driver will have
to map multiple Xen PFN in a single Linux page.
Note that this solution works on page granularity which is a multiple of
4KB.
Signed-off-by: Julien Grall <julien.grall@...rix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: David Vrabel <david.vrabel@...rix.com>
---
drivers/xen/privcmd.c | 8 +++++---
drivers/xen/xlate_mmu.c | 31 ++++++++++++++++++++-----------
2 files changed, 25 insertions(+), 14 deletions(-)
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 5a29616..e8714b4 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -446,7 +446,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
return -EINVAL;
}
- nr_pages = m.num;
+ nr_pages = DIV_ROUND_UP_ULL(m.num, PAGE_SIZE / XEN_PAGE_SIZE);
if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
return -EINVAL;
@@ -494,7 +494,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
goto out_unlock;
}
if (xen_feature(XENFEAT_auto_translated_physmap)) {
- ret = alloc_empty_pages(vma, m.num);
+ ret = alloc_empty_pages(vma, nr_pages);
if (ret < 0)
goto out_unlock;
} else
@@ -518,6 +518,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
state.global_error = 0;
state.version = version;
+ BUILD_BUG_ON(((PAGE_SIZE / sizeof(xen_pfn_t)) % XEN_PFN_PER_PAGE) != 0);
/* mmap_batch_fn guarantees ret == 0 */
BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t),
&pagelist, mmap_batch_fn, &state));
@@ -582,12 +583,13 @@ static void privcmd_close(struct vm_area_struct *vma)
{
struct page **pages = vma->vm_private_data;
int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ int nr_pfn = (vma->vm_end - vma->vm_start) >> XEN_PAGE_SHIFT;
int rc;
if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
return;
- rc = xen_unmap_domain_mfn_range(vma, numpgs, pages);
+ rc = xen_unmap_domain_mfn_range(vma, nr_pfn, pages);
if (rc == 0)
free_xenballooned_pages(numpgs, pages);
else
diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index 58a5389..b9dfe1b 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c
@@ -63,6 +63,7 @@ static int map_foreign_page(unsigned long lpfn, unsigned long fgmfn,
struct remap_data {
xen_pfn_t *fgmfn; /* foreign domain's gmfn */
+ xen_pfn_t *egmfn; /* end foreign domain's gmfn */
pgprot_t prot;
domid_t domid;
struct vm_area_struct *vma;
@@ -78,17 +79,23 @@ static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
{
struct remap_data *info = data;
struct page *page = info->pages[info->index++];
- unsigned long pfn = page_to_pfn(page);
- pte_t pte = pte_mkspecial(pfn_pte(pfn, info->prot));
+ unsigned long pfn = xen_page_to_pfn(page);
+ pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), info->prot));
int rc;
-
- rc = map_foreign_page(pfn, *info->fgmfn, info->domid);
- *info->err_ptr++ = rc;
- if (!rc) {
- set_pte_at(info->vma->vm_mm, addr, ptep, pte);
- info->mapped++;
+ uint32_t i;
+
+ for (i = 0; i < XEN_PFN_PER_PAGE; i++) {
+ if (info->fgmfn == info->egmfn)
+ break;
+
+ rc = map_foreign_page(pfn++, *info->fgmfn, info->domid);
+ *info->err_ptr++ = rc;
+ if (!rc) {
+ set_pte_at(info->vma->vm_mm, addr, ptep, pte);
+ info->mapped++;
+ }
+ info->fgmfn++;
}
- info->fgmfn++;
return 0;
}
@@ -102,13 +109,14 @@ int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
{
int err;
struct remap_data data;
- unsigned long range = nr << PAGE_SHIFT;
+ unsigned long range = round_up(nr, XEN_PFN_PER_PAGE) << XEN_PAGE_SHIFT;
/* Kept here for the purpose of making sure code doesn't break
x86 PVOPS */
BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
data.fgmfn = mfn;
+ data.egmfn = mfn + nr;
data.prot = prot;
data.domid = domid;
data.vma = vma;
@@ -132,7 +140,8 @@ int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
struct xen_remove_from_physmap xrp;
unsigned long pfn;
- pfn = page_to_pfn(pages[i]);
+ pfn = xen_page_to_pfn(pages[i / XEN_PFN_PER_PAGE]) +
+ (i % XEN_PFN_PER_PAGE);
xrp.domid = DOMID_SELF;
xrp.gpfn = pfn;
--
2.1.4
--
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