Mailing List Archive

PVH: privcmd changes. PVH only supports the batch interface. To map a
foreign page to a process, pfn must be allocated. PVH path uses
ballooning for that purpose. The returned pfn is then mapped to the
foreign page. xen_unmap_domain_mfn_range() is introduced to unmap these
pages via the privcmd close call.

Signed-off-by: Mukesh R <mukesh.rathor@oracle.com>
---
drivers/xen/privcmd.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 63d9ee8..b76d33c 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -33,11 +33,14 @@
#include <xen/features.h>
#include <xen/page.h>
#include <xen/xen-ops.h>
+#include <xen/balloon.h>

#include "privcmd.h"

MODULE_LICENSE("GPL");

+#define PRIV_VMA_LOCKED ((void *)1)
+
#ifndef HAVE_ARCH_PRIVCMD_MMAP
static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma);
#endif
@@ -199,6 +202,10 @@ static long privcmd_ioctl_mmap(void __user *udata)
if (!xen_initial_domain())
return -EPERM;

+ /* We only support privcmd_ioctl_mmap_batch for auto translated. */
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return -ENOSYS;
+
if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
return -EFAULT;

@@ -246,6 +253,7 @@ struct mmap_batch_state {
domid_t domain;
unsigned long va;
struct vm_area_struct *vma;
+ int index;
/* A tristate:
* 0 for no errors
* 1 if at least one error has happened (and no
@@ -260,15 +268,24 @@ struct mmap_batch_state {
xen_pfn_t __user *user_mfn;
};

+/* auto translated dom0 note: if domU being created is PV, then mfn is
+ * mfn(addr on bus). If it's auto xlated, then mfn is pfn (input to HAP).
+ */
static int mmap_batch_fn(void *data, void *state)
{
xen_pfn_t *mfnp = data;
struct mmap_batch_state *st = state;
+ struct vm_area_struct *vma = st->vma;
+ struct page **pages = vma->vm_private_data;
+ struct page *cur_page = NULL;
int ret;

+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ cur_page = pages[st->index++];
+
ret = xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
st->vma->vm_page_prot, st->domain,
- NULL);
+ &cur_page);

/* Store error code for second pass. */
*(st->err++) = ret;
@@ -304,6 +321,32 @@ static int mmap_return_errors_v1(void *data, void *state)
return __put_user(*mfnp, st->user_mfn++);
}

+/* Allocate pfns that are then mapped with gmfns from foreign domid. Update
+ * the vma with the page info to use later.
+ * Returns: 0 if success, otherwise -errno
+ */
+static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs)
+{
+ int rc;
+ struct page **pages;
+
+ pages = kcalloc(numpgs, sizeof(pages[0]), GFP_KERNEL);
+ if (pages == NULL)
+ return -ENOMEM;
+
+ rc = alloc_xenballooned_pages(numpgs, pages, 0);
+ if (rc != 0) {
+ pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__,
+ numpgs, rc);
+ kfree(pages);
+ return -ENOMEM;
+ }
+ BUG_ON(vma->vm_private_data != PRIV_VMA_LOCKED);
+ vma->vm_private_data = pages;
+
+ return 0;
+}
+
static struct vm_operations_struct privcmd_vm_ops;

static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
@@ -371,10 +414,18 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
up_write(&mm->mmap_sem);
goto out;
}
+ if (xen_feature(XENFEAT_auto_translated_physmap)) {
+ ret = alloc_empty_pages(vma, m.num);
+ if (ret < 0) {
+ up_write(&mm->mmap_sem);
+ goto out;
+ }
+ }

state.domain = m.dom;
state.vma = vma;
state.va = m.addr;
+ state.index = 0;
state.global_error = 0;
state.err = err_array;

@@ -439,6 +490,20 @@ static long privcmd_ioctl(struct file *file,
return ret;
}

+static void privcmd_close(struct vm_area_struct *vma)
+{
+ struct page **pages = vma ? vma->vm_private_data : NULL;
+ int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+
+ if (!pages || !numpgs || !xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
+ xen_unmap_domain_mfn_range(vma);
+ while (numpgs--)
+ free_xenballooned_pages(1, &pages[numpgs]);
+ kfree(pages);
+}
+
static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
@@ -449,6 +514,7 @@ static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
}

static struct vm_operations_struct privcmd_vm_ops = {
+ .close = privcmd_close,
.fault = privcmd_fault
};

@@ -465,7 +531,7 @@ static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)

static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma)
{
- return (xchg(&vma->vm_private_data, (void *)1) == NULL);
+ return !cmpxchg(&vma->vm_private_data, NULL, PRIV_VMA_LOCKED);
}

const struct file_operations xen_privcmd_fops = {
--
1.7.2.3


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