From d0d87226f535965b4dafc6ef79246456503a4503 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 11 Jul 2024 18:27:44 -0400 Subject: [PATCH] KVM: guest_memfd: return folio from __kvm_gmem_get_pfn() Right now this is simply more consistent and avoids use of pfn_to_page() and put_page(). It will be put to more use in upcoming patches, to ensure that the up-to-date flag is set at the very end of both the kvm_gmem_get_pfn() and kvm_gmem_populate() flows. Reviewed-by: Michael Roth Signed-off-by: Paolo Bonzini --- virt/kvm/guest_memfd.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 1c509c351261..522e1b28e7ae 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -541,34 +541,34 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot) fput(file); } -static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, - gfn_t gfn, kvm_pfn_t *pfn, int *max_order, bool prepare) +static struct folio * +__kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, + gfn_t gfn, kvm_pfn_t *pfn, int *max_order, bool prepare) { pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff; struct kvm_gmem *gmem = file->private_data; struct folio *folio; struct page *page; - int r; if (file != slot->gmem.file) { WARN_ON_ONCE(slot->gmem.file); - return -EFAULT; + return ERR_PTR(-EFAULT); } gmem = file->private_data; if (xa_load(&gmem->bindings, index) != slot) { WARN_ON_ONCE(xa_load(&gmem->bindings, index)); - return -EIO; + return ERR_PTR(-EIO); } folio = kvm_gmem_get_folio(file_inode(file), index, prepare); if (IS_ERR(folio)) - return PTR_ERR(folio); + return folio; if (folio_test_hwpoison(folio)) { folio_unlock(folio); folio_put(folio); - return -EHWPOISON; + return ERR_PTR(-EHWPOISON); } page = folio_file_page(folio, index); @@ -577,25 +577,25 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, if (max_order) *max_order = 0; - r = 0; - folio_unlock(folio); - - return r; + return folio; } int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, kvm_pfn_t *pfn, int *max_order) { struct file *file = kvm_gmem_get_file(slot); - int r; + struct folio *folio; if (!file) return -EFAULT; - r = __kvm_gmem_get_pfn(file, slot, gfn, pfn, max_order, true); + folio = __kvm_gmem_get_pfn(file, slot, gfn, pfn, max_order, true); fput(file); - return r; + if (IS_ERR(folio)) + return PTR_ERR(folio); + + return 0; } EXPORT_SYMBOL_GPL(kvm_gmem_get_pfn); @@ -625,6 +625,7 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long npages = min_t(ulong, slot->npages - (start_gfn - slot->base_gfn), npages); for (i = 0; i < npages; i += (1 << max_order)) { + struct folio *folio; gfn_t gfn = start_gfn + i; kvm_pfn_t pfn; @@ -633,9 +634,11 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long break; } - ret = __kvm_gmem_get_pfn(file, slot, gfn, &pfn, &max_order, false); - if (ret) + folio = __kvm_gmem_get_pfn(file, slot, gfn, &pfn, &max_order, false); + if (IS_ERR(folio)) { + ret = PTR_ERR(folio); break; + } if (!IS_ALIGNED(gfn, (1 << max_order)) || (npages - i) < (1 << max_order)) @@ -644,7 +647,7 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long p = src ? src + i * PAGE_SIZE : NULL; ret = post_populate(kvm, gfn, pfn, p, max_order, opaque); - put_page(pfn_to_page(pfn)); + folio_put(folio); if (ret) break; }