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@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index b199ad3..df2e6f7 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -446,7 +446,7 @@
return -EINVAL;
}
- nr_pages = m.num;
+ nr_pages = DIV_ROUND_UP(m.num, XEN_PFN_PER_PAGE);
if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
return -EINVAL;
@@ -494,7 +494,7 @@
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 @@
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 @@
{
struct page **pages = vma->vm_private_data;
int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ int numgfns = (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_gfn_range(vma, numpgs, pages);
+ rc = xen_unmap_domain_gfn_range(vma, numgfns, 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 cff2387..5063c5e 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c
@@ -38,31 +38,28 @@
#include <xen/interface/xen.h>
#include <xen/interface/memory.h>
-/* map fgfn of domid to lpfn in the current domain */
-static int map_foreign_page(unsigned long lpfn, unsigned long fgfn,
- unsigned int domid)
+typedef void (*xen_gfn_fn_t)(unsigned long gfn, void *data);
+
+/* Break down the pages in 4KB chunk and call fn for each gfn */
+static void xen_for_each_gfn(struct page **pages, unsigned nr_gfn,
+ xen_gfn_fn_t fn, void *data)
{
- int rc;
- struct xen_add_to_physmap_range xatp = {
- .domid = DOMID_SELF,
- .foreign_domid = domid,
- .size = 1,
- .space = XENMAPSPACE_gmfn_foreign,
- };
- xen_ulong_t idx = fgfn;
- xen_pfn_t gpfn = lpfn;
- int err = 0;
+ unsigned long xen_pfn = 0;
+ struct page *page;
+ int i;
- set_xen_guest_handle(xatp.idxs, &idx);
- set_xen_guest_handle(xatp.gpfns, &gpfn);
- set_xen_guest_handle(xatp.errs, &err);
-
- rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
- return rc < 0 ? rc : err;
+ for (i = 0; i < nr_gfn; i++) {
+ if ((i % XEN_PFN_PER_PAGE) == 0) {
+ page = pages[i / XEN_PFN_PER_PAGE];
+ xen_pfn = page_to_xen_pfn(page);
+ }
+ fn(pfn_to_gfn(xen_pfn++), data);
+ }
}
struct remap_data {
xen_pfn_t *fgfn; /* foreign domain's gfn */
+ int nr_fgfn; /* Number of foreign gfn left to map */
pgprot_t prot;
domid_t domid;
struct vm_area_struct *vma;
@@ -71,24 +68,71 @@
struct xen_remap_gfn_info *info;
int *err_ptr;
int mapped;
+
+ /* Hypercall parameters */
+ int h_errs[XEN_PFN_PER_PAGE];
+ xen_ulong_t h_idxs[XEN_PFN_PER_PAGE];
+ xen_pfn_t h_gpfns[XEN_PFN_PER_PAGE];
+
+ int h_iter; /* Iterator */
};
+static void setup_hparams(unsigned long gfn, void *data)
+{
+ struct remap_data *info = data;
+
+ info->h_idxs[info->h_iter] = *info->fgfn;
+ info->h_gpfns[info->h_iter] = gfn;
+ info->h_errs[info->h_iter] = 0;
+
+ info->h_iter++;
+ info->fgfn++;
+}
+
static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
void *data)
{
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));
- int rc;
+ pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), info->prot));
+ int rc, nr_gfn;
+ uint32_t i;
+ struct xen_add_to_physmap_range xatp = {
+ .domid = DOMID_SELF,
+ .foreign_domid = info->domid,
+ .space = XENMAPSPACE_gmfn_foreign,
+ };
- rc = map_foreign_page(pfn, *info->fgfn, info->domid);
- *info->err_ptr++ = rc;
- if (!rc) {
- set_pte_at(info->vma->vm_mm, addr, ptep, pte);
- info->mapped++;
+ nr_gfn = min_t(typeof(info->nr_fgfn), XEN_PFN_PER_PAGE, info->nr_fgfn);
+ info->nr_fgfn -= nr_gfn;
+
+ info->h_iter = 0;
+ xen_for_each_gfn(&page, nr_gfn, setup_hparams, info);
+ BUG_ON(info->h_iter != nr_gfn);
+
+ set_xen_guest_handle(xatp.idxs, info->h_idxs);
+ set_xen_guest_handle(xatp.gpfns, info->h_gpfns);
+ set_xen_guest_handle(xatp.errs, info->h_errs);
+ xatp.size = nr_gfn;
+
+ rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
+
+ /* info->err_ptr expect to have one error status per Xen PFN */
+ for (i = 0; i < nr_gfn; i++) {
+ int err = (rc < 0) ? rc : info->h_errs[i];
+
+ *(info->err_ptr++) = err;
+ if (!err)
+ info->mapped++;
}
- info->fgfn++;
+
+ /*
+ * Note: The hypercall will return 0 in most of the case if even if
+ * all the fgmfn are not mapped. We still have to update the pte
+ * as the userspace may decide to continue.
+ */
+ if (!rc)
+ set_pte_at(info->vma->vm_mm, addr, ptep, pte);
return 0;
}
@@ -102,13 +146,14 @@
{
int err;
struct remap_data data;
- unsigned long range = nr << PAGE_SHIFT;
+ unsigned long range = DIV_ROUND_UP(nr, XEN_PFN_PER_PAGE) << 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.fgfn = gfn;
+ data.nr_fgfn = nr;
data.prot = prot;
data.domid = domid;
data.vma = vma;
@@ -123,21 +168,20 @@
}
EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_array);
+static void unmap_gfn(unsigned long gfn, void *data)
+{
+ struct xen_remove_from_physmap xrp;
+
+ xrp.domid = DOMID_SELF;
+ xrp.gpfn = gfn;
+ (void)HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
+}
+
int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
int nr, struct page **pages)
{
- int i;
+ xen_for_each_gfn(pages, nr, unmap_gfn, NULL);
- for (i = 0; i < nr; i++) {
- struct xen_remove_from_physmap xrp;
- unsigned long pfn;
-
- pfn = page_to_pfn(pages[i]);
-
- xrp.domid = DOMID_SELF;
- xrp.gpfn = pfn;
- (void)HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
- }
return 0;
}
EXPORT_SYMBOL_GPL(xen_xlate_unmap_gfn_range);