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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-12 22:20:28 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-12 22:20:28 +0900
commitccff9b1db693062b0a9c9070f4304deb47ef215c (patch)
treea956cc800a03f11254105fbd9926bab537b6863f /arch/x86/xen/mmu.c
parent3dc329baa2ed1740036183041cefaf8ceb714038 (diff)
parentcb6b6df111e46b9d0f79eb971575fd50555f43f4 (diff)
Merge tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
Pull Xen fixes from Konrad Rzeszutek Wilk: "This has four bug-fixes and one tiny feature that I forgot to put initially in my tree due to oversight. The feature is for kdump kernels to speed up the /proc/vmcore reading. There is a ram_is_pfn helper function that the different platforms can register for. We are now doing that. The bug-fixes cover some embarrassing struct pv_cpu_ops variables being set to NULL on Xen (but not baremetal). We had a similar issue in the past with {write|read}_msr_safe and this fills the three missing ones. The other bug-fix is to make the console output (hvc) be capable of dealing with misbehaving backends and not fall flat on its face. Lastly, a quirk for older XenBus implementations that came with an ancient v3.4 hypervisor (so RHEL5 based) - reading of certain non-existent attributes just hangs the guest during bootup - so we take precaution of not doing that on such older installations. Feature: - Register a pfn_is_ram helper to speed up reading of /proc/vmcore. Bug-fixes: - Three pvops call for Xen were undefined causing BUG_ONs. - Add a quirk so that the shutdown watches (used by kdump) are not used with older Xen (3.4). - Fix ungraceful state transition for the HVC console." * tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches. xen/bootup: allow {read|write}_cr8 pvops call. xen/bootup: allow read_tscp call for Xen PV guests. xen pv-on-hvm: add pfn_is_ram helper for kdump xen/hvc: handle backend CLOSED without CLOSING
Diffstat (limited to 'arch/x86/xen/mmu.c')
-rw-r--r--arch/x86/xen/mmu.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index fd28d86fe3d2..6226c99729b9 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -47,6 +47,7 @@
#include <linux/gfp.h>
#include <linux/memblock.h>
#include <linux/seq_file.h>
+#include <linux/crash_dump.h>
#include <trace/events/xen.h>
@@ -2381,6 +2382,43 @@ void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
#ifdef CONFIG_XEN_PVHVM
+#ifdef CONFIG_PROC_VMCORE
+/*
+ * This function is used in two contexts:
+ * - the kdump kernel has to check whether a pfn of the crashed kernel
+ * was a ballooned page. vmcore is using this function to decide
+ * whether to access a pfn of the crashed kernel.
+ * - the kexec kernel has to check whether a pfn was ballooned by the
+ * previous kernel. If the pfn is ballooned, handle it properly.
+ * Returns 0 if the pfn is not backed by a RAM page, the caller may
+ * handle the pfn special in this case.
+ */
+static int xen_oldmem_pfn_is_ram(unsigned long pfn)
+{
+ struct xen_hvm_get_mem_type a = {
+ .domid = DOMID_SELF,
+ .pfn = pfn,
+ };
+ int ram;
+
+ if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
+ return -ENXIO;
+
+ switch (a.mem_type) {
+ case HVMMEM_mmio_dm:
+ ram = 0;
+ break;
+ case HVMMEM_ram_rw:
+ case HVMMEM_ram_ro:
+ default:
+ ram = 1;
+ break;
+ }
+
+ return ram;
+}
+#endif
+
static void xen_hvm_exit_mmap(struct mm_struct *mm)
{
struct xen_hvm_pagetable_dying a;
@@ -2411,6 +2449,9 @@ void __init xen_hvm_init_mmu_ops(void)
{
if (is_pagetable_dying_supported())
pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
+#ifdef CONFIG_PROC_VMCORE
+ register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
+#endif
}
#endif