linux-kernel - [PATCH] xen mtrr: Add xen_{get,set}

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Date:	Fri, 27 Feb 2009 17:59:25 -0800
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	the arch/x86 maintainers <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Xen-devel <xen-devel@...ts.xensource.com>,
	Mark McLoughlin <markmc@...hat.com>
Subject: [PATCH] xen mtrr: Add xen_{get,set}_mtrr() implementations

From: Mark McLoughlin <markmc@...hat.com>

Straightforward apart from the hack to turn mtrr_ops->set()
into a no-op on all but one CPU.

Signed-off-by: Mark McLoughlin <markmc@...hat.com>
---
 arch/x86/kernel/cpu/mtrr/xen.c |   52 ++++++++++++++++++++++++++++++++++++---
 1 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/xen.c b/arch/x86/kernel/cpu/mtrr/xen.c
index d715843..50a45db 100644
--- a/arch/x86/kernel/cpu/mtrr/xen.c
+++ b/arch/x86/kernel/cpu/mtrr/xen.c
@@ -9,6 +9,52 @@
 
 static int __init xen_num_var_ranges(void);
 
+static void xen_set_mtrr(unsigned int reg, unsigned long base,
+			 unsigned long size, mtrr_type type)
+{
+	struct xen_platform_op op;
+	int error;
+
+	/* mtrr_ops->set() is called once per CPU,
+	 * but Xen's ops apply to all CPUs.
+	 */
+	if (smp_processor_id())
+		return;
+
+	if (size == 0) {
+		op.cmd = XENPF_del_memtype;
+		op.u.del_memtype.handle = 0;
+		op.u.del_memtype.reg    = reg;
+	} else {
+		op.cmd = XENPF_add_memtype;
+		op.u.add_memtype.mfn     = base;
+		op.u.add_memtype.nr_mfns = size;
+		op.u.add_memtype.type    = type;
+	}
+
+	error = HYPERVISOR_dom0_op(&op);
+	BUG_ON(error != 0);
+}
+
+static void xen_get_mtrr(unsigned int reg, unsigned long *base,
+			 unsigned long *size, mtrr_type *type)
+{
+	struct xen_platform_op op;
+
+	op.cmd = XENPF_read_memtype;
+	op.u.read_memtype.reg = reg;
+	if (HYPERVISOR_dom0_op(&op) != 0) {
+		*base = 0;
+		*size = 0;
+		*type = 0;
+		return;
+	}
+
+	*size = op.u.read_memtype.nr_mfns;
+	*base = op.u.read_memtype.mfn;
+	*type = op.u.read_memtype.type;
+}
+
 static int xen_get_free_region(unsigned long base, unsigned long size, int replace_reg)
 {
 	struct xen_platform_op op;
@@ -34,12 +80,10 @@ static int xen_get_free_region(unsigned long base, unsigned long size, int repla
 	return replace_reg;
 }
 
-/* DOM0 TODO: Need to fill in the remaining mtrr methods to have full
- * working userland mtrr support. */
 static struct mtrr_ops xen_mtrr_ops = {
 	.vendor            = X86_VENDOR_UNKNOWN,
-//	.set               = xen_set_mtrr,
-//	.get               = xen_get_mtrr,
+	.set               = xen_set_mtrr,
+	.get               = xen_get_mtrr,
 	.get_free_region   = xen_get_free_region,
 	.validate_add_page = generic_validate_add_page,
 	.have_wrcomb       = positive_have_wrcomb,
-- 
1.6.0.6

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