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Commit d71f5139 authored by Mukesh Rathor's avatar Mukesh Rathor Committed by Ian Campbell
Browse files

xen: privcmd: support autotranslated physmap guests. 



PVH and ARM only support the batch interface. To map a foreign page to
a process, the PFN must be allocated and the autotranslated 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.

Acked-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: default avatarMukesh Rathor <mukesh.rathor@oracle.com>
[v1: Fix up privcmd_close]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
[v2: used for ARM too]
parent 9a032e39

drivers/xen/privcmd.c

+67 −2
Original line number Diff line number Diff line
@@ -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 +490,19 @@ static long privcmd_ioctl(struct file *file, 
	return ret;

}



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;



	if (!xen_feature(XENFEAT_auto_translated_physmap || !numpgs || !pages))

		return;



	xen_unmap_domain_mfn_range(vma, numpgs, pages);

	free_xenballooned_pages(numpgs, pages);

	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 +513,7 @@ 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

};
@@ -466,7 +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 = {