linux-kernel - [PATCHv3 03/10] x86/xen: discard RAM regions above the maximum reservation

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Message-ID: <1438275792-5726-4-git-send-email-david.vrabel@citrix.com>
Date:	Thu, 30 Jul 2015 18:03:05 +0100
From:	David Vrabel <david.vrabel@...rix.com>
To:	<linux-kernel@...r.kernel.org>, <xen-devel@...ts.xenproject.org>
CC:	David Vrabel <david.vrabel@...rix.com>, <linux-mm@...ck.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@...cle.com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Daniel Kiper <daniel.kiper@...cle.com>
Subject: [PATCHv3 03/10] x86/xen: discard RAM regions above the maximum reservation

During setup, discard RAM regions that are above the maximum
reservation (instead of marking them as E820_UNUSABLE).  This allows
hotplug memory to be placed at these addresses.

Signed-off-by: David Vrabel <david.vrabel@...rix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@...cle.com>
---
 arch/x86/xen/setup.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 55f388e..32910c5 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -646,6 +646,7 @@ char * __init xen_memory_setup(void)
 		phys_addr_t addr = map[i].addr;
 		phys_addr_t size = map[i].size;
 		u32 type = map[i].type;
+		bool discard = false;
 
 		if (type == E820_RAM) {
 			if (addr < mem_end) {
@@ -656,10 +657,11 @@ char * __init xen_memory_setup(void)
 				xen_add_extra_mem(addr, size);
 				xen_max_p2m_pfn = PFN_DOWN(addr + size);
 			} else
-				type = E820_UNUSABLE;
+				discard = true;
 		}
 
-		xen_align_and_add_e820_region(addr, size, type);
+		if (!discard)
+			xen_align_and_add_e820_region(addr, size, type);
 
 		map[i].addr += size;
 		map[i].size -= size;
-- 
2.1.4

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