linux-kernel - [PATCH 01/10] xen: Make all reserved pages for the balloon be INVALID_P2M

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 21 Dec 2010 16:37:31 -0500
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	linux-kernel@...r.kernel.org, jeremy@...p.org, hpa@...or.com
Cc:	Jan Beulich <JBeulich@...ell.com>, xen-devel@...ts.xensource.com,
	Konrad Rzeszutek Wilk <konrad@...nel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: [PATCH 01/10] xen: Make all reserved pages for the balloon be INVALID_P2M_ENTRY.

This patch prepares ourselves for the case where void entries in the P2M
tree structure do not necessarily imply that the pages are missing.
With this, we diligently set regions that will be used by the
balloon driver to be INVALID_P2M_ENTRY and under the ownership
of the balloon driver.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
---
 arch/x86/xen/setup.c  |    8 ++++++++
 drivers/xen/balloon.c |    1 +
 2 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index b5a7f92..d984d36 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -52,6 +52,8 @@ phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
 
 static __init void xen_add_extra_mem(unsigned long pages)
 {
+	unsigned long pfn;
+
 	u64 size = (u64)pages * PAGE_SIZE;
 	u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
 
@@ -66,6 +68,11 @@ static __init void xen_add_extra_mem(unsigned long pages)
 	xen_extra_mem_size += size;
 
 	xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
+
+	for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++) {
+		BUG_ON(!set_phys_to_machine(pfn, INVALID_P2M_ENTRY));
+		BUG_ON(get_phys_to_machine(pfn) != INVALID_P2M_ENTRY);
+	}
 }
 
 static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
@@ -105,6 +112,7 @@ static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
 		     start, end, ret);
 		if (ret == 1) {
 			set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+			BUG_ON(get_phys_to_machine(pfn) != INVALID_P2M_ENTRY);
 			len++;
 		}
 	}
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 43f9f02..f82bb48 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -297,6 +297,7 @@ static int decrease_reservation(unsigned long nr_pages)
 	for (i = 0; i < nr_pages; i++) {
 		pfn = mfn_to_pfn(frame_list[i]);
 		set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+		BUG_ON(get_phys_to_machine(pfn) != INVALID_P2M_ENTRY);
 		balloon_append(pfn_to_page(pfn));
 	}
 
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/