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KVM: MMU: prepare to support mapping of VM_IO and VM_PFNMAP frames 

Handle VM_IO like VM_PFNMAP, as is common in the rest of Linux; extract
the formula to convert hva->pfn into a new function, which will soon
gain more capabilities.

Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-06-07 16:22:47 +02:00
parent 196f20ca52
commit 92176a8ede
1 changed files with 15 additions and 5 deletions
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20
virt/kvm/kvm_main.c
View File

@ -1442,6 +1442,16 @@ static bool vma_is_valid(struct vm_area_struct *vma, bool write_fault)
return true;
}
static int hva_to_pfn_remapped(struct vm_area_struct *vma,
unsigned long addr, bool *async,
bool write_fault, kvm_pfn_t *p_pfn)
{
*p_pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) +
vma->vm_pgoff;
BUG_ON(!kvm_is_reserved_pfn(*p_pfn));
return 0;
}
/*
* Pin guest page in memory and return its pfn.
* @addr: host virtual address which maps memory to the guest
@ -1461,7 +1471,7 @@ static kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
{
struct vm_area_struct *vma;
kvm_pfn_t pfn = 0;
int npages;
int npages, r;
/* we can do it either atomically or asynchronously, not both */
BUG_ON(atomic && async);
@ -1487,10 +1497,10 @@ static kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
if (vma == NULL)
pfn = KVM_PFN_ERR_FAULT;
else if ((vma->vm_flags & VM_PFNMAP)) {
pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) +
vma->vm_pgoff;
BUG_ON(!kvm_is_reserved_pfn(pfn));
else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) {
r = hva_to_pfn_remapped(vma, addr, async, write_fault, &pfn);
if (r < 0)
pfn = KVM_PFN_ERR_FAULT;
} else {
if (async && vma_is_valid(vma, write_fault))
*async = true;