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Commit 6eaa412f authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

xen: Mark all initial reserved pages for the balloon as INVALID_P2M_ENTRY. 



With this patch, we diligently set regions that will be used by the
balloon driver to be INVALID_P2M_ENTRY and under the ownership
of the balloon driver. We are OK using the __set_phys_to_machine
as we do not expect to be allocating any P2M middle or entries pages.
The set_phys_to_machine has the side-effect of potentially allocating
new pages and we do not want that at this stage.

We can do this because xen_build_mfn_list_list will have already
allocated all such pages up to xen_max_p2m_pfn.

We also move the check for auto translated physmap down the
stack so it is present in __set_phys_to_machine.

[v2: Rebased with mmu->p2m code split]
Reviewed-by: default avatarIan Campbell <ian.campbell@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 1bae4ce2

arch/x86/include/asm/xen/page.h

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ extern unsigned int machine_to_phys_order; 


extern unsigned long get_phys_to_machine(unsigned long pfn);

extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);

extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);



extern int m2p_add_override(unsigned long mfn, struct page *page);

extern int m2p_remove_override(struct page *page);

arch/x86/xen/mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -2074,7 +2074,7 @@ static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order, 
			in_frames[i] = virt_to_mfn(vaddr);



		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);

		set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);

		__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);



		if (out_frames)

			out_frames[i] = virt_to_pfn(vaddr);

arch/x86/xen/p2m.c

+4 −5
Original line number Diff line number Diff line
@@ -365,6 +365,10 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) 
{

	unsigned topidx, mididx, idx;



	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {

		BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);

		return true;

	}

	if (unlikely(pfn >= MAX_P2M_PFN)) {

		BUG_ON(mfn != INVALID_P2M_ENTRY);

		return true;
@@ -384,11 +388,6 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) 


bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)

{

	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {

		BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);

		return true;

	}



	if (unlikely(!__set_phys_to_machine(pfn, mfn)))  {

		if (!alloc_p2m(pfn))

			return false;

arch/x86/xen/setup.c

+6 −1
Original line number Diff line number Diff line
@@ -52,6 +52,8 @@ phys_addr_t xen_extra_mem_start, xen_extra_mem_size; 


static __init void xen_add_extra_mem(unsigned long pages)

{

	unsigned long pfn;



	u64 size = (u64)pages * PAGE_SIZE;

	u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
@@ -66,6 +68,9 @@ static __init void xen_add_extra_mem(unsigned long pages) 
	xen_extra_mem_size += size;



	xen_max_p2m_pfn = PFN_DOWN(extra_start + size);



	for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++)

		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

}



static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
@@ -104,7 +109,7 @@ static unsigned long __init xen_release_chunk(phys_addr_t start_addr, 
		WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",

		     start, end, ret);

		if (ret == 1) {

			set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

			__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

			len++;

		}

	}

drivers/xen/balloon.c

+1 −1
Original line number Diff line number Diff line
@@ -296,7 +296,7 @@ static int decrease_reservation(unsigned long nr_pages) 
	/* No more mappings: invalidate P2M and add to balloon. */

	for (i = 0; i < nr_pages; i++) {

		pfn = mfn_to_pfn(frame_list[i]);

		set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

		balloon_append(pfn_to_page(pfn));

	}