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Commit fce92dce authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Avi Kivity
Browse files

KVM: MMU: filter out the mmio pfn from the fault pfn 



If the page fault is caused by mmio, the gfn can not be found in memslots, and
'bad_pfn' is returned on gfn_to_hva path, so we can use 'bad_pfn' to identify
the mmio page fault.
And, to clarify the meaning of mmio pfn, we return fault page instead of bad
page when the gfn is not allowd to prefetch

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent c3707958

arch/x86/kvm/mmu.c

+2 −2
Original line number Diff line number Diff line
@@ -2085,8 +2085,8 @@ static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, 


	slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log);

	if (!slot) {

		get_page(bad_page);

		return page_to_pfn(bad_page);

		get_page(fault_page);

		return page_to_pfn(fault_page);

	}



	hva = gfn_to_hva_memslot(slot, gfn);

include/linux/kvm_host.h

+5 −0
Original line number Diff line number Diff line
@@ -327,12 +327,17 @@ static inline struct kvm_memslots *kvm_memslots(struct kvm *kvm) 
static inline int is_error_hpa(hpa_t hpa) { return hpa >> HPA_MSB; }



extern struct page *bad_page;

extern struct page *fault_page;



extern pfn_t bad_pfn;

extern pfn_t fault_pfn;



int is_error_page(struct page *page);

int is_error_pfn(pfn_t pfn);

int is_hwpoison_pfn(pfn_t pfn);

int is_fault_pfn(pfn_t pfn);

int is_noslot_pfn(pfn_t pfn);

int is_invalid_pfn(pfn_t pfn);

int kvm_is_error_hva(unsigned long addr);

int kvm_set_memory_region(struct kvm *kvm,

			  struct kvm_userspace_memory_region *mem,

virt/kvm/kvm_main.c

+14 −2
Original line number Diff line number Diff line
@@ -101,8 +101,8 @@ static bool largepages_enabled = true; 
static struct page *hwpoison_page;

static pfn_t hwpoison_pfn;



static struct page *fault_page;

static pfn_t fault_pfn;

struct page *fault_page;

pfn_t fault_pfn;



inline int kvm_is_mmio_pfn(pfn_t pfn)

{
@@ -931,6 +931,18 @@ int is_fault_pfn(pfn_t pfn) 
}

EXPORT_SYMBOL_GPL(is_fault_pfn);



int is_noslot_pfn(pfn_t pfn)

{

	return pfn == bad_pfn;

}

EXPORT_SYMBOL_GPL(is_noslot_pfn);



int is_invalid_pfn(pfn_t pfn)

{

	return pfn == hwpoison_pfn || pfn == fault_pfn;

}

EXPORT_SYMBOL_GPL(is_invalid_pfn);



static inline unsigned long bad_hva(void)

{

	return PAGE_OFFSET;