Commit 6e9f05dc66f9 ("libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE")
...updated MAX_STRUCT_PAGE_SIZE to account for sizeof(struct page)
potentially doubling in the case of CONFIG_KMSAN=y. Unfortunately this
doubles the amount of capacity stolen from user addressable capacity for
everyone, regardless of whether they are using the debug option. Revert
that change, mandate that MAX_STRUCT_PAGE_SIZE never exceed 64, but
allow for debug scenarios to proceed with creating debug sized page maps
with a compile option to support debug scenarios.
Note that this only applies to cases where the page map is permanent,
i.e. stored in a reservation of the pmem itself ("--map=dev" in "ndctl
create-namespace" terms). For the "--map=mem" case, since the allocation
is ephemeral for the lifespan of the namespace, there are no explicit
restriction. However, the implicit restriction, of having enough
available "System RAM" to store the page map for the typically large
pmem, still applies.
Fixes: 6e9f05dc66f9 ("libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE")
Cc: <stable(a)vger.kernel.org>
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Marco Elver <elver(a)google.com>
Reported-by: Jeff Moyer <jmoyer(a)redhat.com>
---
Changes since v1 [1]:
* Replace the module option with a compile option and a description of
the tradeoffs to consider when running with KMSAN enabled in the
presence of NVDIMM namespaces and their local reservation of capacity
for a 'struct page' memmap array. (Greg)
[1]: https://lore.kernel.org/all/63bc8fec4744a_5178e29467@dwillia2-xfh.jf.intel.…
drivers/nvdimm/Kconfig | 19 +++++++++++++++++++
drivers/nvdimm/nd.h | 2 +-
drivers/nvdimm/pfn_devs.c | 42 +++++++++++++++++++++++++++---------------
3 files changed, 47 insertions(+), 16 deletions(-)
diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index 79d93126453d..77b06d54cc62 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -102,6 +102,25 @@ config NVDIMM_KEYS
depends on ENCRYPTED_KEYS
depends on (LIBNVDIMM=ENCRYPTED_KEYS) || LIBNVDIMM=m
+config NVDIMM_KMSAN
+ bool
+ depends on KMSAN
+ help
+ KMSAN, and other memory debug facilities, increase the size of
+ 'struct page' to contain extra metadata. This collides with
+ the NVDIMM capability to store a potentially
+ larger-than-"System RAM" size 'struct page' array in a
+ reservation of persistent memory rather than limited /
+ precious DRAM. However, that reservation needs to persist for
+ the life of the given NVDIMM namespace. If you are using KMSAN
+ to debug an issue unrelated to NVDIMMs or DAX then say N to this
+ option. Otherwise, say Y but understand that any namespaces
+ (with the page array stored pmem) created with this build of
+ the kernel will permanently reserve and strand excess
+ capacity compared to the CONFIG_KMSAN=n case.
+
+ Select N if unsure.
+
config NVDIMM_TEST_BUILD
tristate "Build the unit test core"
depends on m
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 85ca5b4da3cf..ec5219680092 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -652,7 +652,7 @@ void devm_namespace_disable(struct device *dev,
struct nd_namespace_common *ndns);
#if IS_ENABLED(CONFIG_ND_CLAIM)
/* max struct page size independent of kernel config */
-#define MAX_STRUCT_PAGE_SIZE 128
+#define MAX_STRUCT_PAGE_SIZE 64
int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap);
#else
static inline int nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 61af072ac98f..c7655a1fe38c 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -13,6 +13,8 @@
#include "pfn.h"
#include "nd.h"
+const static bool page_struct_override = IS_ENABLED(CONFIG_NVDIMM_KMSAN);
+
static void nd_pfn_release(struct device *dev)
{
struct nd_region *nd_region = to_nd_region(dev->parent);
@@ -758,12 +760,6 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
return -ENXIO;
}
- /*
- * Note, we use 64 here for the standard size of struct page,
- * debugging options may cause it to be larger in which case the
- * implementation will limit the pfns advertised through
- * ->direct_access() to those that are included in the memmap.
- */
start = nsio->res.start;
size = resource_size(&nsio->res);
npfns = PHYS_PFN(size - SZ_8K);
@@ -782,20 +778,33 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
}
end_trunc = start + size - ALIGN_DOWN(start + size, align);
if (nd_pfn->mode == PFN_MODE_PMEM) {
+ unsigned long page_map_size = MAX_STRUCT_PAGE_SIZE * npfns;
+
/*
* The altmap should be padded out to the block size used
* when populating the vmemmap. This *should* be equal to
* PMD_SIZE for most architectures.
*
- * Also make sure size of struct page is less than 128. We
- * want to make sure we use large enough size here so that
- * we don't have a dynamic reserve space depending on
- * struct page size. But we also want to make sure we notice
- * when we end up adding new elements to struct page.
+ * Also make sure size of struct page is less than
+ * MAX_STRUCT_PAGE_SIZE. The goal here is compatibility in the
+ * face of production kernel configurations that reduce the
+ * 'struct page' size below MAX_STRUCT_PAGE_SIZE. For debug
+ * kernel configurations that increase the 'struct page' size
+ * above MAX_STRUCT_PAGE_SIZE, the page_struct_override allows
+ * for continuing with the capacity that will be wasted when
+ * reverting to a production kernel configuration. Otherwise,
+ * those configurations are blocked by default.
*/
- BUILD_BUG_ON(sizeof(struct page) > MAX_STRUCT_PAGE_SIZE);
- offset = ALIGN(start + SZ_8K + MAX_STRUCT_PAGE_SIZE * npfns, align)
- - start;
+ if (sizeof(struct page) > MAX_STRUCT_PAGE_SIZE) {
+ if (page_struct_override)
+ page_map_size = sizeof(struct page) * npfns;
+ else {
+ dev_err(&nd_pfn->dev,
+ "Memory debug options prevent using pmem for the page map\n");
+ return -EINVAL;
+ }
+ }
+ offset = ALIGN(start + SZ_8K + page_map_size, align) - start;
} else if (nd_pfn->mode == PFN_MODE_RAM)
offset = ALIGN(start + SZ_8K, align) - start;
else
@@ -818,7 +827,10 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
pfn_sb->version_minor = cpu_to_le16(4);
pfn_sb->end_trunc = cpu_to_le32(end_trunc);
pfn_sb->align = cpu_to_le32(nd_pfn->align);
- pfn_sb->page_struct_size = cpu_to_le16(MAX_STRUCT_PAGE_SIZE);
+ if (sizeof(struct page) > MAX_STRUCT_PAGE_SIZE && page_struct_override)
+ pfn_sb->page_struct_size = cpu_to_le16(sizeof(struct page));
+ else
+ pfn_sb->page_struct_size = cpu_to_le16(MAX_STRUCT_PAGE_SIZE);
pfn_sb->page_size = cpu_to_le32(PAGE_SIZE);
checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
pfn_sb->checksum = cpu_to_le64(checksum);
Use the correct old/new topology and payload states in
intel_mst_disable_dp(). So far drm_atomic_get_mst_topology_state() it
used returned either the old state, in case the state was added already
earlier during the atomic check phase or otherwise the new state (but
the latter could fail, which can't be handled in the enable/disable
hooks). After the first patch in the patchset, the state should always
get added already during the check phase, so here we can get the
old/new states without a failure.
drm_dp_remove_payload() should use time_slots from the old payload state
and vc_start_slot in the new one. It should update the new payload
states to reflect the sink's current payload table after the payload is
removed. Pass the new topology state and the old and new payload states
accordingly.
This also fixes a problem where the payload allocations for multiple MST
streams on the same link got inconsistent after a few commits, as
during payload removal the old instead of the new payload state got
updated, so the subsequent enabling sequence and commits used a stale
payload state.
v2: Constify the old payload state pointer. (Ville)
Cc: Lyude Paul <lyude(a)redhat.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Cc: stable(a)vger.kernel.org # 6.1
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Signed-off-by: Imre Deak <imre.deak(a)intel.com>
---
drivers/gpu/drm/i915/display/intel_dp_mst.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index dc4e5ff1dbb31..054a009e800d7 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -524,10 +524,14 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
struct intel_dp *intel_dp = &dig_port->dp;
struct intel_connector *connector =
to_intel_connector(old_conn_state->connector);
- struct drm_dp_mst_topology_state *mst_state =
- drm_atomic_get_mst_topology_state(&state->base, &intel_dp->mst_mgr);
- struct drm_dp_mst_atomic_payload *payload =
- drm_atomic_get_mst_payload_state(mst_state, connector->port);
+ struct drm_dp_mst_topology_state *old_mst_state =
+ drm_atomic_get_old_mst_topology_state(&state->base, &intel_dp->mst_mgr);
+ struct drm_dp_mst_topology_state *new_mst_state =
+ drm_atomic_get_new_mst_topology_state(&state->base, &intel_dp->mst_mgr);
+ const struct drm_dp_mst_atomic_payload *old_payload =
+ drm_atomic_get_mst_payload_state(old_mst_state, connector->port);
+ struct drm_dp_mst_atomic_payload *new_payload =
+ drm_atomic_get_mst_payload_state(new_mst_state, connector->port);
struct drm_i915_private *i915 = to_i915(connector->base.dev);
drm_dbg_kms(&i915->drm, "active links %d\n",
@@ -535,8 +539,8 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
intel_hdcp_disable(intel_mst->connector);
- drm_dp_remove_payload(&intel_dp->mst_mgr, mst_state,
- payload, payload);
+ drm_dp_remove_payload(&intel_dp->mst_mgr, new_mst_state,
+ old_payload, new_payload);
intel_audio_codec_disable(encoder, old_crtc_state, old_conn_state);
}
--
2.37.1
Add a function to get the old MST topology state, required by a
follow-up i915 patch.
While at it clarify the code comment of
drm_atomic_get_new_mst_topology_state() and add _new prefix
to the new state pointer to remind about its difference from the old
state.
v2: Use old_/new_ prefixes for the state pointers. (Ville)
Cc: Lyude Paul <lyude(a)redhat.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Cc: stable(a)vger.kernel.org # 6.1
Cc: dri-devel(a)lists.freedesktop.org
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Signed-off-by: Imre Deak <imre.deak(a)intel.com>
---
drivers/gpu/drm/display/drm_dp_mst_topology.c | 33 ++++++++++++++++---
include/drm/display/drm_dp_mst_helper.h | 3 ++
2 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 1990ff5dc7ddd..38dab76ae69ea 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -5364,28 +5364,53 @@ struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_a
}
EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
+/**
+ * drm_atomic_get_old_mst_topology_state: get old MST topology state in atomic state, if any
+ * @state: global atomic state
+ * @mgr: MST topology manager, also the private object in this case
+ *
+ * This function wraps drm_atomic_get_old_private_obj_state() passing in the MST atomic
+ * state vtable so that the private object state returned is that of a MST
+ * topology object.
+ *
+ * Returns:
+ *
+ * The old MST topology state, or NULL if there's no topology state for this MST mgr
+ * in the global atomic state
+ */
+struct drm_dp_mst_topology_state *
+drm_atomic_get_old_mst_topology_state(struct drm_atomic_state *state,
+ struct drm_dp_mst_topology_mgr *mgr)
+{
+ struct drm_private_state *old_priv_state =
+ drm_atomic_get_old_private_obj_state(state, &mgr->base);
+
+ return old_priv_state ? to_dp_mst_topology_state(old_priv_state) : NULL;
+}
+EXPORT_SYMBOL(drm_atomic_get_old_mst_topology_state);
+
/**
* drm_atomic_get_new_mst_topology_state: get new MST topology state in atomic state, if any
* @state: global atomic state
* @mgr: MST topology manager, also the private object in this case
*
- * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
+ * This function wraps drm_atomic_get_new_private_obj_state() passing in the MST atomic
* state vtable so that the private object state returned is that of a MST
* topology object.
*
* Returns:
*
- * The MST topology state, or NULL if there's no topology state for this MST mgr
+ * The new MST topology state, or NULL if there's no topology state for this MST mgr
* in the global atomic state
*/
struct drm_dp_mst_topology_state *
drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
struct drm_dp_mst_topology_mgr *mgr)
{
- struct drm_private_state *priv_state =
+ struct drm_private_state *new_priv_state =
drm_atomic_get_new_private_obj_state(state, &mgr->base);
- return priv_state ? to_dp_mst_topology_state(priv_state) : NULL;
+ return new_priv_state ? to_dp_mst_topology_state(new_priv_state) : NULL;
}
EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
index f5eb9aa152b14..32c764fb9cb56 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -868,6 +868,9 @@ struct drm_dp_mst_topology_state *
drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
struct drm_dp_mst_topology_mgr *mgr);
struct drm_dp_mst_topology_state *
+drm_atomic_get_old_mst_topology_state(struct drm_atomic_state *state,
+ struct drm_dp_mst_topology_mgr *mgr);
+struct drm_dp_mst_topology_state *
drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
struct drm_dp_mst_topology_mgr *mgr);
struct drm_dp_mst_atomic_payload *
--
2.37.1
Add the MST topology for a CRTC to the atomic state if the driver
needs to force a modeset on the CRTC after the encoder compute config
functions are called.
Later the MST encoder's disable hook also adds the state, but that isn't
guaranteed to work (since in that hook getting the state may fail, which
can't be handled there). This should fix that, while a later patch fixes
the use of the MST state in the disable hook.
v2: Add missing forward struct declartions, caught by hdrtest.
v3: Factor out intel_dp_mst_add_topology_state_for_connector() used
later in the patchset.
Cc: Lyude Paul <lyude(a)redhat.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Cc: stable(a)vger.kernel.org # 6.1
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com> # v2
Signed-off-by: Imre Deak <imre.deak(a)intel.com>
---
drivers/gpu/drm/i915/display/intel_display.c | 4 ++
drivers/gpu/drm/i915/display/intel_dp_mst.c | 61 ++++++++++++++++++++
drivers/gpu/drm/i915/display/intel_dp_mst.h | 4 ++
3 files changed, 69 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 166662ade593c..38106cf63b3b9 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -5936,6 +5936,10 @@ int intel_modeset_all_pipes(struct intel_atomic_state *state,
if (ret)
return ret;
+ ret = intel_dp_mst_add_topology_state_for_crtc(state, crtc);
+ if (ret)
+ return ret;
+
ret = intel_atomic_add_affected_planes(state, crtc);
if (ret)
return ret;
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 8b0e4defa3f10..f3cb12dcfe0a7 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -1223,3 +1223,64 @@ bool intel_dp_mst_is_slave_trans(const struct intel_crtc_state *crtc_state)
return crtc_state->mst_master_transcoder != INVALID_TRANSCODER &&
crtc_state->mst_master_transcoder != crtc_state->cpu_transcoder;
}
+
+/**
+ * intel_dp_mst_add_topology_state_for_connector - add MST topology state for a connector
+ * @state: atomic state
+ * @connector: connector to add the state for
+ * @crtc: the CRTC @connector is attached to
+ *
+ * Add the MST topology state for @connector to @state.
+ *
+ * Returns 0 on success, negative error code on failure.
+ */
+static int
+intel_dp_mst_add_topology_state_for_connector(struct intel_atomic_state *state,
+ struct intel_connector *connector,
+ struct intel_crtc *crtc)
+{
+ struct drm_dp_mst_topology_state *mst_state;
+
+ if (!connector->mst_port)
+ return 0;
+
+ mst_state = drm_atomic_get_mst_topology_state(&state->base,
+ &connector->mst_port->mst_mgr);
+ if (IS_ERR(mst_state))
+ return PTR_ERR(mst_state);
+
+ mst_state->pending_crtc_mask |= drm_crtc_mask(&crtc->base);
+
+ return 0;
+}
+
+/**
+ * intel_dp_mst_add_topology_state_for_crtc - add MST topology state for a CRTC
+ * @state: atomic state
+ * @crtc: CRTC to add the state for
+ *
+ * Add the MST topology state for @crtc to @state.
+ *
+ * Returns 0 on success, negative error code on failure.
+ */
+int intel_dp_mst_add_topology_state_for_crtc(struct intel_atomic_state *state,
+ struct intel_crtc *crtc)
+{
+ struct drm_connector *_connector;
+ struct drm_connector_state *conn_state;
+ int i;
+
+ for_each_new_connector_in_state(&state->base, _connector, conn_state, i) {
+ struct intel_connector *connector = to_intel_connector(_connector);
+ int ret;
+
+ if (conn_state->crtc != &crtc->base)
+ continue;
+
+ ret = intel_dp_mst_add_topology_state_for_connector(state, connector, crtc);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h b/drivers/gpu/drm/i915/display/intel_dp_mst.h
index f7301de6cdfb3..f1815bb722672 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.h
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.h
@@ -8,6 +8,8 @@
#include <linux/types.h>
+struct intel_atomic_state;
+struct intel_crtc;
struct intel_crtc_state;
struct intel_digital_port;
struct intel_dp;
@@ -18,5 +20,7 @@ int intel_dp_mst_encoder_active_links(struct intel_digital_port *dig_port);
bool intel_dp_mst_is_master_trans(const struct intel_crtc_state *crtc_state);
bool intel_dp_mst_is_slave_trans(const struct intel_crtc_state *crtc_state);
bool intel_dp_mst_source_support(struct intel_dp *intel_dp);
+int intel_dp_mst_add_topology_state_for_crtc(struct intel_atomic_state *state,
+ struct intel_crtc *crtc);
#endif /* __INTEL_DP_MST_H__ */
--
2.37.1