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Subject[PATCH] xen mtrr: Implement xen_get_free_region()
Date
From: Mark McLoughlin <markmc@redhat.com>

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@redhat.com>
---
arch/x86/kernel/cpu/mtrr/xen.c | 27 ++++++++++++++++++++++++++-
1 files changed, 26 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/mtrr/xen.c b/arch/x86/kernel/cpu/mtrr/xen.c
index f226044..d715843 100644
--- a/arch/x86/kernel/cpu/mtrr/xen.c
+++ b/arch/x86/kernel/cpu/mtrr/xen.c
@@ -9,13 +9,38 @@

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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