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Merge branch 'for-6.5/cxl-region-fixes' into for-6.5/cxl

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Pick up the recent fixes to how CPU caches are managed relative to
region setup / teardown, and make sure that all decoders transition
successfully before updating the region state from COMMIT => ACTIVE.
This commit is contained in:
Dan Williams
2023-06-25 17:23:50 -07:00
parent aeaefabc59 adfe19738b
commit e2c18eb50c
2 changed files with 72 additions and 46 deletions
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102
drivers/cxl/core/region.c
View File

@@ -125,10 +125,38 @@ static struct cxl_region_ref *cxl_rr_load(struct cxl_port *port,
return xa_load(&port->regions, (unsigned long)cxlr);
}
static int cxl_region_invalidate_memregion(struct cxl_region *cxlr)
{
if (!cpu_cache_has_invalidate_memregion()) {
if (IS_ENABLED(CONFIG_CXL_REGION_INVALIDATION_TEST)) {
dev_warn_once(
&cxlr->dev,
"Bypassing cpu_cache_invalidate_memregion() for testing!\n");
return 0;
} else {
dev_err(&cxlr->dev,
"Failed to synchronize CPU cache state\n");
return -ENXIO;
}
}
cpu_cache_invalidate_memregion(IORES_DESC_CXL);
return 0;
}
static int cxl_region_decode_reset(struct cxl_region *cxlr, int count)
{
struct cxl_region_params *p = &cxlr->params;
int i;
int i, rc = 0;
/*
* Before region teardown attempt to flush, and if the flush
* fails cancel the region teardown for data consistency
* concerns
*/
rc = cxl_region_invalidate_memregion(cxlr);
if (rc)
return rc;
for (i = count - 1; i >= 0; i--) {
struct cxl_endpoint_decoder *cxled = p->targets[i];
@@ -136,7 +164,6 @@ static int cxl_region_decode_reset(struct cxl_region *cxlr, int count)
struct cxl_port *iter = cxled_to_port(cxled);
struct cxl_dev_state *cxlds = cxlmd->cxlds;
struct cxl_ep *ep;
int rc = 0;
if (cxlds->rcd)
goto endpoint_reset;
@@ -155,14 +182,19 @@ static int cxl_region_decode_reset(struct cxl_region *cxlr, int count)
rc = cxld->reset(cxld);
if (rc)
return rc;
set_bit(CXL_REGION_F_NEEDS_RESET, &cxlr->flags);
}
endpoint_reset:
rc = cxled->cxld.reset(&cxled->cxld);
if (rc)
return rc;
set_bit(CXL_REGION_F_NEEDS_RESET, &cxlr->flags);
}
/* all decoders associated with this region have been torn down */
clear_bit(CXL_REGION_F_NEEDS_RESET, &cxlr->flags);
return 0;
}
@@ -256,9 +288,19 @@ static ssize_t commit_store(struct device *dev, struct device_attribute *attr,
goto out;
}
if (commit)
/*
* Invalidate caches before region setup to drop any speculative
* consumption of this address space
*/
rc = cxl_region_invalidate_memregion(cxlr);
if (rc)
return rc;
if (commit) {
rc = cxl_region_decode_commit(cxlr);
else {
if (rc == 0)
p->state = CXL_CONFIG_COMMIT;
} else {
p->state = CXL_CONFIG_RESET_PENDING;
up_write(&cxl_region_rwsem);
device_release_driver(&cxlr->dev);
@@ -268,18 +310,20 @@ static ssize_t commit_store(struct device *dev, struct device_attribute *attr,
* The lock was dropped, so need to revalidate that the reset is
* still pending.
*/
if (p->state == CXL_CONFIG_RESET_PENDING)
if (p->state == CXL_CONFIG_RESET_PENDING) {
rc = cxl_region_decode_reset(cxlr, p->interleave_ways);
/*
* Revert to committed since there may still be active
* decoders associated with this region, or move forward
* to active to mark the reset successful
*/
if (rc)
p->state = CXL_CONFIG_COMMIT;
else
p->state = CXL_CONFIG_ACTIVE;
}
}
if (rc)
goto out;
if (commit)
p->state = CXL_CONFIG_COMMIT;
else if (p->state == CXL_CONFIG_RESET_PENDING)
p->state = CXL_CONFIG_ACTIVE;
out:
up_write(&cxl_region_rwsem);
@@ -1686,7 +1730,6 @@ static int cxl_region_attach(struct cxl_region *cxlr,
if (rc)
goto err_decrement;
p->state = CXL_CONFIG_ACTIVE;
set_bit(CXL_REGION_F_INCOHERENT, &cxlr->flags);
}
cxled->cxld.interleave_ways = p->interleave_ways;
@@ -2815,30 +2858,6 @@ out:
}
EXPORT_SYMBOL_NS_GPL(cxl_add_to_region, CXL);
static int cxl_region_invalidate_memregion(struct cxl_region *cxlr)
{
if (!test_bit(CXL_REGION_F_INCOHERENT, &cxlr->flags))
return 0;
if (!cpu_cache_has_invalidate_memregion()) {
if (IS_ENABLED(CONFIG_CXL_REGION_INVALIDATION_TEST)) {
dev_warn_once(
&cxlr->dev,
"Bypassing cpu_cache_invalidate_memregion() for testing!\n");
clear_bit(CXL_REGION_F_INCOHERENT, &cxlr->flags);
return 0;
} else {
dev_err(&cxlr->dev,
"Failed to synchronize CPU cache state\n");
return -ENXIO;
}
}
cpu_cache_invalidate_memregion(IORES_DESC_CXL);
clear_bit(CXL_REGION_F_INCOHERENT, &cxlr->flags);
return 0;
}
static int is_system_ram(struct resource *res, void *arg)
{
struct cxl_region *cxlr = arg;
@@ -2866,7 +2885,12 @@ static int cxl_region_probe(struct device *dev)
goto out;
}
rc = cxl_region_invalidate_memregion(cxlr);
if (test_bit(CXL_REGION_F_NEEDS_RESET, &cxlr->flags)) {
dev_err(&cxlr->dev,
"failed to activate, re-commit region and retry\n");
rc = -ENXIO;
goto out;
}
/*
* From this point on any path that changes the region's state away from

16
drivers/cxl/cxl.h
View File

@@ -470,18 +470,20 @@ struct cxl_region_params {
int nr_targets;
};
/*
* Flag whether this region needs to have its HPA span synchronized with
* CPU cache state at region activation time.
*/
#define CXL_REGION_F_INCOHERENT 0
/*
* Indicate whether this region has been assembled by autodetection or
* userspace assembly. Prevent endpoint decoders outside of automatic
* detection from being added to the region.
*/
#define CXL_REGION_F_AUTO 1
#define CXL_REGION_F_AUTO 0
/*
* Require that a committed region successfully complete a teardown once
* any of its associated decoders have been torn down. This maintains
* the commit state for the region since there are committed decoders,
* but blocks cxl_region_probe().
*/
#define CXL_REGION_F_NEEDS_RESET 1
/**
* struct cxl_region - CXL region