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authorLinus Torvalds <torvalds@linux-foundation.org>2012-06-15 17:17:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-06-15 17:17:15 -0700
commit069915b94642b05c9b45fee36862157026b36614 (patch)
treeb983c4968a7483f22bf64ea5c1c70e00daa9f455 /arch/x86
parent41c8c535237e9cea522024548c5bc37f7d34a81f (diff)
parentb9e0d95c041ca2d7ad297ee37c2e9cfab67a188f (diff)
Merge tag 'stable/for-linus-3.5-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
Pull five Xen bug-fixes from Konrad Rzeszutek Wilk: - When booting as PVHVM we would try to use PV console - but would not validate the parameters causing us to crash during restore b/c we re-use the wrong event channel. - When booting on machines with SR-IOV PCI bridge we didn't check for the bridge and tried to use it. - Under AMD machines would advertise the APERFMPERF resulting in needless amount of MSRs from the guest. - A global value (xen_released_pages) was not subtracted at bootup when pages were added back in. This resulted in the balloon worker having the wrong account of how many pages were truly released. - Fix dead-lock when xen-blkfront is run in the same domain as xen-blkback. * tag 'stable/for-linus-3.5-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen: mark local pages as FOREIGN in the m2p_override xen/setup: filter APERFMPERF cpuid feature out xen/balloon: Subtract from xen_released_pages the count that is populated. xen/pci: Check for PCI bridge before using it. xen/events: Add WARN_ON when quick lookup found invalid type. xen/hvc: Check HVM_PARAM_CONSOLE_[EVTCHN|PFN] for correctness. xen/hvc: Fix error cases around HVM_PARAM_CONSOLE_PFN xen/hvc: Collapse error logic.
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/xen/enlighten.c8
-rw-r--r--arch/x86/xen/p2m.c36
-rw-r--r--arch/x86/xen/setup.c3
3 files changed, 46 insertions, 1 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index e74df9548a02..ff962d4b821e 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -209,6 +209,9 @@ static void __init xen_banner(void)
xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
}
+#define CPUID_THERM_POWER_LEAF 6
+#define APERFMPERF_PRESENT 0
+
static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0;
static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0;
@@ -242,6 +245,11 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
*dx = cpuid_leaf5_edx_val;
return;
+ case CPUID_THERM_POWER_LEAF:
+ /* Disabling APERFMPERF for kernel usage */
+ maskecx = ~(1 << APERFMPERF_PRESENT);
+ break;
+
case 0xb:
/* Suppress extended topology stuff */
maskebx = 0;
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index ffd08c414e91..64effdc6da94 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -706,6 +706,7 @@ int m2p_add_override(unsigned long mfn, struct page *page,
unsigned long uninitialized_var(address);
unsigned level;
pte_t *ptep = NULL;
+ int ret = 0;
pfn = page_to_pfn(page);
if (!PageHighMem(page)) {
@@ -741,6 +742,24 @@ int m2p_add_override(unsigned long mfn, struct page *page,
list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]);
spin_unlock_irqrestore(&m2p_override_lock, flags);
+ /* p2m(m2p(mfn)) == mfn: the mfn is already present somewhere in
+ * this domain. Set the FOREIGN_FRAME_BIT in the p2m for the other
+ * pfn so that the following mfn_to_pfn(mfn) calls will return the
+ * pfn from the m2p_override (the backend pfn) instead.
+ * We need to do this because the pages shared by the frontend
+ * (xen-blkfront) can be already locked (lock_page, called by
+ * do_read_cache_page); when the userspace backend tries to use them
+ * with direct_IO, mfn_to_pfn returns the pfn of the frontend, so
+ * do_blockdev_direct_IO is going to try to lock the same pages
+ * again resulting in a deadlock.
+ * As a side effect get_user_pages_fast might not be safe on the
+ * frontend pages while they are being shared with the backend,
+ * because mfn_to_pfn (that ends up being called by GUPF) will
+ * return the backend pfn rather than the frontend pfn. */
+ ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
+ if (ret == 0 && get_phys_to_machine(pfn) == mfn)
+ set_phys_to_machine(pfn, FOREIGN_FRAME(mfn));
+
return 0;
}
EXPORT_SYMBOL_GPL(m2p_add_override);
@@ -752,6 +771,7 @@ int m2p_remove_override(struct page *page, bool clear_pte)
unsigned long uninitialized_var(address);
unsigned level;
pte_t *ptep = NULL;
+ int ret = 0;
pfn = page_to_pfn(page);
mfn = get_phys_to_machine(pfn);
@@ -821,6 +841,22 @@ int m2p_remove_override(struct page *page, bool clear_pte)
} else
set_phys_to_machine(pfn, page->index);
+ /* p2m(m2p(mfn)) == FOREIGN_FRAME(mfn): the mfn is already present
+ * somewhere in this domain, even before being added to the
+ * m2p_override (see comment above in m2p_add_override).
+ * If there are no other entries in the m2p_override corresponding
+ * to this mfn, then remove the FOREIGN_FRAME_BIT from the p2m for
+ * the original pfn (the one shared by the frontend): the backend
+ * cannot do any IO on this page anymore because it has been
+ * unshared. Removing the FOREIGN_FRAME_BIT from the p2m entry of
+ * the original pfn causes mfn_to_pfn(mfn) to return the frontend
+ * pfn again. */
+ mfn &= ~FOREIGN_FRAME_BIT;
+ ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
+ if (ret == 0 && get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) &&
+ m2p_find_override(mfn) == NULL)
+ set_phys_to_machine(pfn, mfn);
+
return 0;
}
EXPORT_SYMBOL_GPL(m2p_remove_override);
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 3ebba0753d38..a4790bf22c59 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -371,7 +371,8 @@ char * __init xen_memory_setup(void)
populated = xen_populate_chunk(map, memmap.nr_entries,
max_pfn, &last_pfn, xen_released_pages);
- extra_pages += (xen_released_pages - populated);
+ xen_released_pages -= populated;
+ extra_pages += xen_released_pages;
if (last_pfn > max_pfn) {
max_pfn = min(MAX_DOMAIN_PAGES, last_pfn);