From 3b1b3d7af2528f6932e67e0181acbdb30ad1bb9f Mon Sep 17 00:00:00 2001 From: Mukesh Rathor Date: Wed, 17 Oct 2012 17:11:21 -0700 Subject: [PATCH] xen/pvh: /dev/xen/privcmd changes. PVH only supports the batch interface. To map a foreign page to a process, the PFN must be allocated and 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. Acked-by: Stefano Stabellini Signed-off-by: Mukesh Rathor [v1: Fix up privcmd_close] Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/privcmd.c | 69 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 67 insertions(+), 2 deletions(-) diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index b612267a8cb6..b9d08987a5a5 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -33,11 +33,14 @@ #include #include #include +#include #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 = { -- 2.39.5