From: Mark McLoughlin <markmc@xxxxxxxxxx>
When an already set MTRR is being changed, we need to
first unset, since Xen also maintains a usage count.
Signed-off-by: Mark McLoughlin <markmc@xxxxxxxxxx>
---
arch/x86/kernel/cpu/mtrr/mtrr.h | 2 ++
arch/x86/kernel/cpu/mtrr/xen.c | 27 ++++++++++++++++++++++++++-
2 files changed, 28 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.h b/arch/x86/kernel/cpu/mtrr/mtrr.h
index eb23ca2..6142d6e 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.h
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.h
@@ -5,6 +5,8 @@
#include <linux/types.h>
#include <linux/stddef.h>
+#include <asm/mtrr.h>
+
#define MTRRcap_MSR 0x0fe
#define MTRRdefType_MSR 0x2ff
diff --git a/arch/x86/kernel/cpu/mtrr/xen.c b/arch/x86/kernel/cpu/mtrr/xen.c
index 622d075..1ffb93c 100644
--- a/arch/x86/kernel/cpu/mtrr/xen.c
+++ b/arch/x86/kernel/cpu/mtrr/xen.c
@@ -15,13 +15,38 @@
static int __init xen_num_var_ranges(void);
+static int xen_get_free_region(unsigned long base, unsigned long size, int
replace_reg)
+{
+ struct xen_platform_op op;
+ int error;
+
+ if (replace_reg < 0)
+ return generic_get_free_region(base, size, -1);
+
+ /* If we're replacing the contents of a register,
+ * we need to first unset it since Xen also keeps
+ * a usage count.
+ */
+ op.cmd = XENPF_del_memtype;
+ op.u.del_memtype.handle = 0;
+ op.u.del_memtype.reg = replace_reg;
+
+ error = HYPERVISOR_dom0_op(&op);
+ if (error) {
+ BUG_ON(error > 0);
+ return error;
+ }
+
+ 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,
- .get_free_region = generic_get_free_region,
+ .get_free_region = xen_get_free_region,
.validate_add_page = generic_validate_add_page,
.have_wrcomb = positive_have_wrcomb,
.use_intel_if = 0,
--
1.6.0.6
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