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Subject[RFC PATCH V2 15/22] x86/intel_rdt: Prevent new allocations from pseudo-locked regions
Date
When a user requests a new cache allocation we need to enforce that it
does not intersect with an existing pseudo-locked region. An allocation
with a bitmask intersection with a pseudo-locked region will enable
cache allocations to that region and thus evict pseudo-locked data.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
---
arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
index 4a11aea3ad2c..4f823d631345 100644
--- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
+++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
@@ -136,8 +136,10 @@ static bool cbm_validate(char *buf, unsigned long *data, struct rdt_resource *r)
}

/*
- * Read one cache bit mask (hex). Check that it is valid for the current
- * resource type.
+ * Read one cache bit mask (hex). Check that it is valid and available for
+ * the current resource type. While CAT allows CBM to overlap amongst
+ * classes of service we do not allow a CBM to overlap with a region that has
+ * been pseudo-locked.
*/
int parse_cbm(char *buf, struct rdt_resource *r, struct rdt_domain *d)
{
@@ -150,6 +152,8 @@ int parse_cbm(char *buf, struct rdt_resource *r, struct rdt_domain *d)

if(!cbm_validate(buf, &data, r))
return -EINVAL;
+ if (cbm_pseudo_locked(data, d))
+ return -EINVAL;
d->new_ctrl = data;
d->have_new_ctrl = true;

--
2.13.6
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