[PATCH 10/19] KVM: Use follow_pfnmap API

Peter Xu
2024-08-09T16:09:47Z

Use the new pfnmap API to allow huge MMIO mappings for VMs. The rest work
is done perfectly on the other side (host_pfn_mapping_level()).

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
virt/kvm/kvm_main.c | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d0788d0a72cc..9fb1c527a8e1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2862,13 +2862,11 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
unsigned long addr, bool write_fault,
bool *writable, kvm_pfn_t *p_pfn)
{
+ struct follow_pfnmap_args args = { .vma = vma, .address = addr };
kvm_pfn_t pfn;
- pte_t *ptep;
- pte_t pte;
- spinlock_t *ptl;
int r;

- r = follow_pte(vma, addr, &ptep, &ptl);
+ r = follow_pfnmap_start(&args);
if (r) {
/*
* get_user_pages fails for VM_IO and VM_PFNMAP vmas and does
@@ -2883,21 +2881,19 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
if (r)
return r;

- r = follow_pte(vma, addr, &ptep, &ptl);
+ r = follow_pfnmap_start(&args);
if (r)
return r;
}

- pte = ptep_get(ptep);
-
- if (write_fault && !pte_write(pte)) {
+ if (write_fault && !args.writable) {
pfn = KVM_PFN_ERR_RO_FAULT;
goto out;
}

if (writable)
- *writable = pte_write(pte);
- pfn = pte_pfn(pte);
+ *writable = args.writable;
+ pfn = args.pfn;

/*
* Get a reference here because callers of *hva_to_pfn* and
@@ -2918,9 +2914,8 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
*/
if (!kvm_try_get_pfn(pfn))
r = -EFAULT;
-
out:
- pte_unmap_unlock(ptep, ptl);
+ follow_pfnmap_end(&args);
*p_pfn = pfn;

return r;
--
2.45.0