Commit 20ca57cd authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'stable/for-linus-3.18-b-rc1-tag' of... 

Merge tag 'stable/for-linus-3.18-b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen bug fixes from David Vrabel:

 - Fix regression in xen_clocksource_read() which caused all Xen guests
   to crash early in boot.
 - Several fixes for super rare race conditions in the p2m.
 - Assorted other minor fixes.

* tag 'stable/for-linus-3.18-b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pci: Allocate memory for physdev_pci_device_add's optarr
  x86/xen: panic on bad Xen-provided memory map
  x86/xen: Fix incorrect per_cpu accessor in xen_clocksource_read()
  x86/xen: avoid race in p2m handling
  x86/xen: delay construction of mfn_list_list
  x86/xen: avoid writing to freed memory after race in p2m handling
  xen/balloon: Don't continue ballooning when BP_ECANCELED is encountered
parents c6d13403 486edb24

arch/x86/xen/enlighten.c

+0 −3
Original line number Diff line number Diff line
@@ -1636,9 +1636,6 @@ asmlinkage __visible void __init xen_start_kernel(void) 
	xen_raw_console_write("mapping kernel into physical memory\n");

	xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, xen_start_info->nr_pages);



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

	xen_build_mfn_list_list();



	/* keep using Xen gdt for now; no urgent need to change it */



#ifdef CONFIG_X86_32

arch/x86/xen/mmu.c

+4 −1
Original line number Diff line number Diff line
@@ -1217,10 +1217,13 @@ static void __init xen_pagetable_p2m_copy(void) 
static void __init xen_pagetable_init(void)

{

	paging_init();

	xen_setup_shared_info();

#ifdef CONFIG_X86_64

	xen_pagetable_p2m_copy();

#endif

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

	xen_build_mfn_list_list();



	xen_setup_shared_info();

	xen_post_allocator_init();

}

static void xen_write_cr2(unsigned long cr2)

arch/x86/xen/p2m.c

+25 −58
Original line number Diff line number Diff line
@@ -163,6 +163,7 @@ 
#include <linux/hash.h>

#include <linux/sched.h>

#include <linux/seq_file.h>

#include <linux/bootmem.h>



#include <asm/cache.h>

#include <asm/setup.h>
@@ -181,21 +182,20 @@ static void __init m2p_override_init(void); 


unsigned long xen_max_p2m_pfn __read_mostly;



static unsigned long *p2m_mid_missing_mfn;

static unsigned long *p2m_top_mfn;

static unsigned long **p2m_top_mfn_p;



/* Placeholders for holes in the address space */

static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE);

static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE);

static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE);



static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);

static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE);

static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE);



static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE);

static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_identity, P2M_MID_PER_PAGE);

static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_identity_mfn, P2M_MID_PER_PAGE);



RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));

RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));



/* For each I/O range remapped we may lose up to two leaf pages for the boundary

 * violations and three mid pages to cover up to 3GB. With
@@ -272,11 +272,11 @@ static void p2m_init(unsigned long *p2m) 
 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures

 *

 * This is called both at boot time, and after resuming from suspend:

 * - At boot time we're called very early, and must use extend_brk()

 * - At boot time we're called rather early, and must use alloc_bootmem*()

 *   to allocate memory.

 *

 * - After resume we're called from within stop_machine, but the mfn

 *   tree should alreay be completely allocated.

 *   tree should already be completely allocated.

 */

void __ref xen_build_mfn_list_list(void)

{
@@ -287,20 +287,17 @@ void __ref xen_build_mfn_list_list(void) 


	/* Pre-initialize p2m_top_mfn to be completely missing */

	if (p2m_top_mfn == NULL) {

		p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);

		p2m_mid_missing_mfn = alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);

		p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);

		p2m_mid_identity_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);

		p2m_mid_mfn_init(p2m_mid_identity_mfn, p2m_identity);



		p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);

		p2m_top_mfn_p = alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);

		p2m_top_mfn_p_init(p2m_top_mfn_p);



		p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);

		p2m_top_mfn = alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);

		p2m_top_mfn_init(p2m_top_mfn);

	} else {

		/* Reinitialise, mfn's all change after migration */

		p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);

		p2m_mid_mfn_init(p2m_mid_identity_mfn, p2m_identity);

	}



	for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) {
@@ -328,10 +325,9 @@ void __ref xen_build_mfn_list_list(void) 
			/*

			 * XXX boot-time only!  We should never find

			 * missing parts of the mfn tree after

			 * runtime.  extend_brk() will BUG if we call

			 * it too late.

			 * runtime.

			 */

			mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);

			mid_mfn_p = alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);

			p2m_mid_mfn_init(mid_mfn_p, p2m_missing);



			p2m_top_mfn_p[topidx] = mid_mfn_p;
@@ -415,7 +411,6 @@ void __init xen_build_dynamic_phys_to_machine(void) 
	m2p_override_init();

}

#ifdef CONFIG_X86_64

#include <linux/bootmem.h>

unsigned long __init xen_revector_p2m_tree(void)

{

	unsigned long va_start;
@@ -477,7 +472,6 @@ unsigned long __init xen_revector_p2m_tree(void) 


			copy_page(new, mid_p);

			p2m_top[topidx][mididx] = &mfn_list[pfn_free];

			p2m_top_mfn_p[topidx][mididx] = virt_to_mfn(&mfn_list[pfn_free]);



			pfn_free += P2M_PER_PAGE;
@@ -538,12 +532,13 @@ static bool alloc_p2m(unsigned long pfn) 
	unsigned topidx, mididx;

	unsigned long ***top_p, **mid;

	unsigned long *top_mfn_p, *mid_mfn;

	unsigned long *p2m_orig;



	topidx = p2m_top_index(pfn);

	mididx = p2m_mid_index(pfn);



	top_p = &p2m_top[topidx];

	mid = *top_p;

	mid = ACCESS_ONCE(*top_p);



	if (mid == p2m_mid_missing) {

		/* Mid level is missing, allocate a new one */
@@ -558,7 +553,7 @@ static bool alloc_p2m(unsigned long pfn) 
	}



	top_mfn_p = &p2m_top_mfn[topidx];

	mid_mfn = p2m_top_mfn_p[topidx];

	mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);



	BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
@@ -566,6 +561,7 @@ static bool alloc_p2m(unsigned long pfn) 
		/* Separately check the mid mfn level */

		unsigned long missing_mfn;

		unsigned long mid_mfn_mfn;

		unsigned long old_mfn;



		mid_mfn = alloc_p2m_page();

		if (!mid_mfn)
@@ -575,17 +571,19 @@ static bool alloc_p2m(unsigned long pfn) 


		missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);

		mid_mfn_mfn = virt_to_mfn(mid_mfn);

		if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn)

		old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);

		if (old_mfn != missing_mfn) {

			free_p2m_page(mid_mfn);

		else

			mid_mfn = mfn_to_virt(old_mfn);

		} else {

			p2m_top_mfn_p[topidx] = mid_mfn;

		}

	}



	if (p2m_top[topidx][mididx] == p2m_identity ||

	    p2m_top[topidx][mididx] == p2m_missing) {

	p2m_orig = ACCESS_ONCE(p2m_top[topidx][mididx]);

	if (p2m_orig == p2m_identity || p2m_orig == p2m_missing) {

		/* p2m leaf page is missing */

		unsigned long *p2m;

		unsigned long *p2m_orig = p2m_top[topidx][mididx];



		p2m = alloc_p2m_page();

		if (!p2m)
@@ -606,7 +604,6 @@ static bool __init early_alloc_p2m(unsigned long pfn, bool check_boundary) 
{

	unsigned topidx, mididx, idx;

	unsigned long *p2m;

	unsigned long *mid_mfn_p;



	topidx = p2m_top_index(pfn);

	mididx = p2m_mid_index(pfn);
@@ -633,43 +630,21 @@ static bool __init early_alloc_p2m(unsigned long pfn, bool check_boundary) 


	p2m_top[topidx][mididx] = p2m;



	/* For save/restore we need to MFN of the P2M saved */



	mid_mfn_p = p2m_top_mfn_p[topidx];

	WARN(mid_mfn_p[mididx] != virt_to_mfn(p2m_missing),

		"P2M_TOP_P[%d][%d] != MFN of p2m_missing!\n",

		topidx, mididx);

	mid_mfn_p[mididx] = virt_to_mfn(p2m);



	return true;

}



static bool __init early_alloc_p2m_middle(unsigned long pfn)

{

	unsigned topidx = p2m_top_index(pfn);

	unsigned long *mid_mfn_p;

	unsigned long **mid;



	mid = p2m_top[topidx];

	mid_mfn_p = p2m_top_mfn_p[topidx];

	if (mid == p2m_mid_missing) {

		mid = extend_brk(PAGE_SIZE, PAGE_SIZE);



		p2m_mid_init(mid, p2m_missing);



		p2m_top[topidx] = mid;



		BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);

	}

	/* And the save/restore P2M tables.. */

	if (mid_mfn_p == p2m_mid_missing_mfn) {

		mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);

		p2m_mid_mfn_init(mid_mfn_p, p2m_missing);



		p2m_top_mfn_p[topidx] = mid_mfn_p;

		p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);

		/* Note: we don't set mid_mfn_p[midix] here,

		 * look in early_alloc_p2m() */

	}

	return true;

}
@@ -680,14 +655,13 @@ static bool __init early_alloc_p2m_middle(unsigned long pfn) 
 * replace the P2M leaf with a p2m_missing or p2m_identity.

 * Stick the old page in the new P2M tree location.

 */

bool __init early_can_reuse_p2m_middle(unsigned long set_pfn, unsigned long set_mfn)

static bool __init early_can_reuse_p2m_middle(unsigned long set_pfn)

{

	unsigned topidx;

	unsigned mididx;

	unsigned ident_pfns;

	unsigned inv_pfns;

	unsigned long *p2m;

	unsigned long *mid_mfn_p;

	unsigned idx;

	unsigned long pfn;
@@ -733,11 +707,6 @@ bool __init early_can_reuse_p2m_middle(unsigned long set_pfn, unsigned long set_ 
found:

	/* Found one, replace old with p2m_identity or p2m_missing */

	p2m_top[topidx][mididx] = (ident_pfns ? p2m_identity : p2m_missing);

	/* And the other for save/restore.. */

	mid_mfn_p = p2m_top_mfn_p[topidx];

	/* NOTE: Even if it is a p2m_identity it should still be point to

	 * a page filled with INVALID_P2M_ENTRY entries. */

	mid_mfn_p[mididx] = virt_to_mfn(p2m_missing);



	/* Reset where we want to stick the old page in. */

	topidx = p2m_top_index(set_pfn);
@@ -752,8 +721,6 @@ found: 


	p2m_init(p2m);

	p2m_top[topidx][mididx] = p2m;

	mid_mfn_p = p2m_top_mfn_p[topidx];

	mid_mfn_p[mididx] = virt_to_mfn(p2m);



	return true;

}
@@ -763,7 +730,7 @@ bool __init early_set_phys_to_machine(unsigned long pfn, unsigned long mfn) 
		if (!early_alloc_p2m_middle(pfn))

			return false;



		if (early_can_reuse_p2m_middle(pfn, mfn))

		if (early_can_reuse_p2m_middle(pfn))

			return __set_phys_to_machine(pfn, mfn);



		if (!early_alloc_p2m(pfn, false /* boundary crossover OK!*/))

arch/x86/xen/setup.c

+1 −0
Original line number Diff line number Diff line
@@ -595,6 +595,7 @@ char * __init xen_memory_setup(void) 
		rc = 0;

	}

	BUG_ON(rc);

	BUG_ON(memmap.nr_entries == 0);



	/*

	 * Xen won't allow a 1:1 mapping to be created to UNUSABLE

arch/x86/xen/time.c

+1 −1
Original line number Diff line number Diff line
@@ -158,7 +158,7 @@ cycle_t xen_clocksource_read(void) 
	cycle_t ret;



	preempt_disable_notrace();

	src = this_cpu_ptr(&xen_vcpu->time);

	src = &__this_cpu_read(xen_vcpu)->time;

	ret = pvclock_clocksource_read(src);

	preempt_enable_notrace();

	return ret;

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