On Tue, Sep 10, 2024 at 11:43:46PM +0000, Ackerley Tng wrote:
If HugeTLB is requested at guest_memfd creation time, HugeTLB pages will be used to back guest_memfd.
Signed-off-by: Ackerley Tng ackerleytng@google.com
virt/kvm/guest_memfd.c | 252 ++++++++++++++++++++++++++++++++++++++--- 1 file changed, 239 insertions(+), 13 deletions(-)
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 31e1115273e1..2e6f12e2bac8 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -8,6 +8,8 @@ #include <linux/pseudo_fs.h> #include <linux/pagemap.h> #include <linux/anon_inodes.h> +#include <linux/memcontrol.h> +#include <linux/mempolicy.h> #include "kvm_mm.h" @@ -29,6 +31,13 @@ static struct kvm_gmem_hugetlb *kvm_gmem_hgmem(struct inode *inode) return inode->i_mapping->i_private_data; } +static bool is_kvm_gmem_hugetlb(struct inode *inode) +{
- u64 flags = (u64)inode->i_private;
- return flags & KVM_GUEST_MEMFD_HUGETLB;
+}
/**
- folio_file_pfn - like folio_file_page, but return a pfn.
- @folio: The folio which contains this index.
@@ -58,6 +67,9 @@ static int __kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slo return 0; } +/**
- Use the uptodate flag to indicate that the folio is prepared for KVM's usage.
- */
static inline void kvm_gmem_mark_prepared(struct folio *folio) { folio_mark_uptodate(folio); @@ -72,13 +84,18 @@ static inline void kvm_gmem_mark_prepared(struct folio *folio) static int kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, struct folio *folio) {
- unsigned long nr_pages, i; pgoff_t index; int r;
- nr_pages = folio_nr_pages(folio);
- for (i = 0; i < nr_pages; i++)
clear_highpage(folio_page(folio, i));
- if (folio_test_hugetlb(folio)) {
folio_zero_user(folio, folio->index << PAGE_SHIFT);
Is (folio->index << PAGE_SHIFT) the right address hint to provide? I don't think we can say the folio will be mapped at this address since this value is an offset into the file. In most cases, I believe it won't be mapped anywhere since we just allocated it.
Thanks, Elliot