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Commit 9b705f0e authored by Stefano Stabellini's avatar Stefano Stabellini Committed by Konrad Rzeszutek Wilk
Browse files

xen p2m: transparently change the p2m mappings in the m2p override 



In m2p_add_override store the original mfn into page->index and then
change the p2m mapping, setting mfns as FOREIGN_FRAME.

In m2p_remove_override restore the original mapping.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent f0a70c88

arch/x86/xen/p2m.c

+12 −0
Original line number Diff line number Diff line
@@ -407,8 +407,11 @@ static unsigned long mfn_hash(unsigned long mfn) 
void m2p_add_override(unsigned long mfn, struct page *page)

{

	unsigned long flags;

	unsigned long pfn = page_to_pfn(page);

	page->private = mfn;

	page->index = pfn_to_mfn(pfn);



	__set_phys_to_machine(pfn, FOREIGN_FRAME(mfn));

	spin_lock_irqsave(&m2p_override_lock, flags);

	list_add(&page->lru,  &m2p_overrides[mfn_hash(mfn)]);

	spin_unlock_irqrestore(&m2p_override_lock, flags);
@@ -417,9 +420,18 @@ void m2p_add_override(unsigned long mfn, struct page *page) 
void m2p_remove_override(struct page *page)

{

	unsigned long flags;

	unsigned long mfn;

	unsigned long pfn;



	pfn = page_to_pfn(page);

	mfn = get_phys_to_machine(pfn);

	if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))

		return;



	spin_lock_irqsave(&m2p_override_lock, flags);

	list_del(&page->lru);

	spin_unlock_irqrestore(&m2p_override_lock, flags);

	__set_phys_to_machine(pfn, page->index);

}



struct page *m2p_find_override(unsigned long mfn)