[PATCH v3] xen,kdump: handle pv domain in paddr_vmcoreinfo_note()

[Juergen Gross]

For kdump to work correctly it needs the physical address of
vmcoreinfo_note. When running as dom0 this means the virtual address
has to be translated to the related machine address.

paddr_vmcoreinfo_note() is meant to do the translation via
__pa_symbol() only, but being attributed "weak" it can be replaced
easily in Xen case.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Tested-by: Petr Tesarik <ptesarik@xxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Reviewed-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
---
Changes in V3:
- rebased to recent Xen patches

Changes in V2:
- use __pa_symbol() (Boris Ostrovsky)
- remove unneeded casts (Jan Beulich)
---
 arch/x86/xen/mmu_pv.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 284d189f40dd..9657187bc7bd 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -49,6 +49,9 @@
 #include <linux/memblock.h>
 #include <linux/seq_file.h>
 #include <linux/crash_dump.h>
+#ifdef CONFIG_KEXEC_CORE
+#include <linux/kexec.h>
+#endif
 
 #include <trace/events/xen.h>
 
@@ -2715,3 +2718,13 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
 	spin_unlock_irqrestore(&xen_reservation_lock, flags);
 }
 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
+
+#ifdef CONFIG_KEXEC_CORE
+phys_addr_t paddr_vmcoreinfo_note(void)
+{
+	if (xen_pv_domain())
+		return virt_to_machine(&vmcoreinfo_note).maddr;
+	else
+		return __pa_symbol(&vmcoreinfo_note);
+}
+#endif /* CONFIG_KEXEC_CORE */
-- 
2.12.0