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Commit 59b29440 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

xen/x86: Use memblock_reserve for sensitive areas. 



instead of a big memblock_reserve. This way we can be more
selective in freeing regions (and it also makes it easier
to understand where is what).

[v1: Move the auto_translate_physmap to proper line]
[v2: Per Stefano suggestion add more comments]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent a3118beb

arch/x86/xen/enlighten.c

+48 −0
Original line number Diff line number Diff line
@@ -998,7 +998,54 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 


	return ret;

}

/*

 * If the MFN is not in the m2p (provided to us by the hypervisor) this

 * function won't do anything. In practice this means that the XenBus

 * MFN won't be available for the initial domain. */

static void __init xen_reserve_mfn(unsigned long mfn)

{

	unsigned long pfn;



	if (!mfn)

		return;

	pfn = mfn_to_pfn(mfn);

	if (phys_to_machine_mapping_valid(pfn))

		memblock_reserve(PFN_PHYS(pfn), PAGE_SIZE);

}

static void __init xen_reserve_internals(void)

{

	unsigned long size;



	if (!xen_pv_domain())

		return;



	/* xen_start_info does not exist in the M2P, hence can't use

	 * xen_reserve_mfn. */

	memblock_reserve(__pa(xen_start_info), PAGE_SIZE);



	xen_reserve_mfn(PFN_DOWN(xen_start_info->shared_info));

	xen_reserve_mfn(xen_start_info->store_mfn);



	if (!xen_initial_domain())

		xen_reserve_mfn(xen_start_info->console.domU.mfn);



	if (xen_feature(XENFEAT_auto_translated_physmap))

		return;



	/*

	 * ALIGN up to compensate for the p2m_page pointing to an array that

	 * can partially filled (look in xen_build_dynamic_phys_to_machine).

	 */



	size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));



	/* We could use xen_reserve_mfn here, but would end up looping quite

	 * a lot (and call memblock_reserve for each PAGE), so lets just use

	 * the easy way and reserve it wholesale. */

	memblock_reserve(__pa(xen_start_info->mfn_list), size);



	/* The pagetables are reserved in mmu.c */

}

void xen_setup_shared_info(void)

{

	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
@@ -1362,6 +1409,7 @@ asmlinkage void __init xen_start_kernel(void) 
	xen_raw_console_write("mapping kernel into physical memory\n");

	pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);



	xen_reserve_internals();

	/* Allocate and initialize top and mid mfn levels for p2m structure */

	xen_build_mfn_list_list();

arch/x86/xen/p2m.c

+5 −0
Original line number Diff line number Diff line
@@ -388,6 +388,11 @@ void __init xen_build_dynamic_phys_to_machine(void) 
	}



	m2p_override_init();



	/* NOTE: We cannot call memblock_reserve here for the mfn_list as there

	 * isn't enough pieces to make it work (for one - we are still using the

	 * Xen provided pagetable). Do it later in xen_reserve_internals.

	 */

}



unsigned long get_phys_to_machine(unsigned long pfn)

arch/x86/xen/setup.c

+0 −9
Original line number Diff line number Diff line
@@ -424,15 +424,6 @@ char * __init xen_memory_setup(void) 
	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,

			E820_RESERVED);



	/*

	 * Reserve Xen bits:

	 *  - mfn_list

	 *  - xen_start_info

	 * See comment above "struct start_info" in <xen/interface/xen.h>

	 */

	memblock_reserve(__pa(xen_start_info->mfn_list),

			 xen_start_info->pt_base - xen_start_info->mfn_list);



	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);



	return "Xen";