The return address of translation functions is not consistently
checked for a valid address. Check if ULLONG_MAX was returned.
Signed-off-by: Robert Richter <rrichter@amd.com>
---
drivers/cxl/core/hdm.c | 2 +-
drivers/cxl/core/region.c | 36 +++++++++++++++++++-------
tools/testing/cxl/test/cxl_translate.c | 4 +--
3 files changed, 29 insertions(+), 13 deletions(-)
diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 1c5d2022c87a..8b50cdce4b29 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -530,7 +530,7 @@ resource_size_t cxl_dpa_size(struct cxl_endpoint_decoder *cxled)
resource_size_t cxl_dpa_resource_start(struct cxl_endpoint_decoder *cxled)
{
- resource_size_t base = -1;
+ resource_size_t base = ULLONG_MAX;
lockdep_assert_held(&cxl_rwsem.dpa);
if (cxled->dpa_res)
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index c7ac78f1b644..2c070c7c7bfe 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3124,7 +3124,7 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
struct cxl_region_params *p = &cxlr->params;
struct cxl_endpoint_decoder *cxled = NULL;
- u64 dpa_offset, hpa_offset, hpa;
+ u64 base, dpa_offset, hpa_offset, hpa;
u16 eig = 0;
u8 eiw = 0;
int pos;
@@ -3142,8 +3142,14 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
ways_to_eiw(p->interleave_ways, &eiw);
granularity_to_eig(p->interleave_granularity, &eig);
- dpa_offset = dpa - cxl_dpa_resource_start(cxled);
+ base = cxl_dpa_resource_start(cxled);
+ if (base == ULLONG_MAX)
+ return ULLONG_MAX;
+
+ dpa_offset = dpa - base;
hpa_offset = cxl_calculate_hpa_offset(dpa_offset, pos, eiw, eig);
+ if (hpa_offset == ULLONG_MAX)
+ return ULLONG_MAX;
/* Apply the hpa_offset to the region base address */
hpa = hpa_offset + p->res->start + p->cache_size;
@@ -3152,6 +3158,9 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
if (cxlrd->ops.hpa_to_spa)
hpa = cxlrd->ops.hpa_to_spa(cxlrd, hpa);
+ if (hpa == ULLONG_MAX)
+ return ULLONG_MAX;
+
if (!cxl_resource_contains_addr(p->res, hpa)) {
dev_dbg(&cxlr->dev,
"Addr trans fail: hpa 0x%llx not in region\n", hpa);
@@ -3176,10 +3185,11 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
struct cxl_region_params *p = &cxlr->params;
struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
struct cxl_endpoint_decoder *cxled;
- u64 hpa, hpa_offset, dpa_offset;
+ u64 hpa_offset = offset;
+ u64 dpa_base, dpa_offset;
u16 eig = 0;
u8 eiw = 0;
- int pos;
+ int pos = -1;
lockdep_assert_held(&cxl_rwsem.region);
lockdep_assert_held(&cxl_rwsem.dpa);
@@ -3193,13 +3203,14 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
* CXL HPA is assumed to equal SPA.
*/
if (cxlrd->ops.spa_to_hpa) {
- hpa = cxlrd->ops.spa_to_hpa(cxlrd, p->res->start + offset);
- hpa_offset = hpa - p->res->start;
- } else {
- hpa_offset = offset;
+ hpa_offset = cxlrd->ops.spa_to_hpa(cxlrd, p->res->start + offset);
+ if (hpa_offset != ULLONG_MAX)
+ hpa_offset -= p->res->start;
}
- pos = cxl_calculate_position(hpa_offset, eiw, eig);
+ if (hpa_offset != ULLONG_MAX)
+ pos = cxl_calculate_position(hpa_offset, eiw, eig);
+
if (pos < 0 || pos >= p->nr_targets) {
dev_dbg(&cxlr->dev, "Invalid position %d for %d targets\n",
pos, p->nr_targets);
@@ -3213,8 +3224,13 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
cxled = p->targets[i];
if (cxled->pos != pos)
continue;
+
+ dpa_base = cxl_dpa_resource_start(cxled);
+ if (dpa_base == ULLONG_MAX)
+ continue;
+
result->cxlmd = cxled_to_memdev(cxled);
- result->dpa = cxl_dpa_resource_start(cxled) + dpa_offset;
+ result->dpa = dpa_base + dpa_offset;
return 0;
}
diff --git a/tools/testing/cxl/test/cxl_translate.c b/tools/testing/cxl/test/cxl_translate.c
index 2200ae21795c..66f8270aacd8 100644
--- a/tools/testing/cxl/test/cxl_translate.c
+++ b/tools/testing/cxl/test/cxl_translate.c
@@ -69,7 +69,7 @@ static u64 to_hpa(u64 dpa_offset, int pos, u8 r_eiw, u16 r_eig, u8 hb_ways,
/* Calculate base HPA offset from DPA and position */
hpa_offset = cxl_calculate_hpa_offset(dpa_offset, pos, r_eiw, r_eig);
- if (math == XOR_MATH) {
+ if (hpa_offset != ULLONG_MAX && math == XOR_MATH) {
cximsd->nr_maps = hbiw_to_nr_maps[hb_ways];
if (cximsd->nr_maps)
return cxl_do_xormap_calc(cximsd, hpa_offset, hb_ways);
@@ -262,7 +262,7 @@ static int test_random_params(void)
reverse_dpa = cxl_calculate_dpa_offset(hpa, eiw, eig);
reverse_pos = cxl_calculate_position(hpa, eiw, eig);
- if (reverse_dpa != dpa || reverse_pos != pos) {
+ if (hpa == ULLONG_MAX || reverse_dpa != dpa || reverse_pos != pos) {
pr_err("test random iter %d FAIL hpa=%llu, dpa=%llu reverse_dpa=%llu, pos=%d reverse_pos=%d eiw=%u eig=%u\n",
i, hpa, dpa, reverse_dpa, pos, reverse_pos, eiw,
eig);
--
2.47.3On Tue, Dec 09, 2025 at 07:06:48PM +0100, Robert Richter wrote:
> The return address of translation functions is not consistently
> checked for a valid address. Check if ULLONG_MAX was returned.
The why of the dpa base address change is not explained as that
That -1 return would be ULLONG_MAX in 64 bit system, so not
clear why the return value of cxl_dpa_resource_start() needs to
change.
Is this is for general cleanup, then, like DaveJ noted, returning
sooner is better. I guess post this as a general cleanup pointing
out why the earlier returns are needed.
>
> Signed-off-by: Robert Richter <rrichter@amd.com>
> ---
> drivers/cxl/core/hdm.c | 2 +-
> drivers/cxl/core/region.c | 36 +++++++++++++++++++-------
> tools/testing/cxl/test/cxl_translate.c | 4 +--
> 3 files changed, 29 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 1c5d2022c87a..8b50cdce4b29 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -530,7 +530,7 @@ resource_size_t cxl_dpa_size(struct cxl_endpoint_decoder *cxled)
>
> resource_size_t cxl_dpa_resource_start(struct cxl_endpoint_decoder *cxled)
> {
> - resource_size_t base = -1;
> + resource_size_t base = ULLONG_MAX;
>
> lockdep_assert_held(&cxl_rwsem.dpa);
> if (cxled->dpa_res)
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index c7ac78f1b644..2c070c7c7bfe 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3124,7 +3124,7 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
> struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
> struct cxl_region_params *p = &cxlr->params;
> struct cxl_endpoint_decoder *cxled = NULL;
> - u64 dpa_offset, hpa_offset, hpa;
> + u64 base, dpa_offset, hpa_offset, hpa;
> u16 eig = 0;
> u8 eiw = 0;
> int pos;
> @@ -3142,8 +3142,14 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
> ways_to_eiw(p->interleave_ways, &eiw);
> granularity_to_eig(p->interleave_granularity, &eig);
>
> - dpa_offset = dpa - cxl_dpa_resource_start(cxled);
> + base = cxl_dpa_resource_start(cxled);
> + if (base == ULLONG_MAX)
> + return ULLONG_MAX;
> +
> + dpa_offset = dpa - base;
> hpa_offset = cxl_calculate_hpa_offset(dpa_offset, pos, eiw, eig);
> + if (hpa_offset == ULLONG_MAX)
> + return ULLONG_MAX;
>
> /* Apply the hpa_offset to the region base address */
> hpa = hpa_offset + p->res->start + p->cache_size;
> @@ -3152,6 +3158,9 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
> if (cxlrd->ops.hpa_to_spa)
> hpa = cxlrd->ops.hpa_to_spa(cxlrd, hpa);
>
> + if (hpa == ULLONG_MAX)
> + return ULLONG_MAX;
> +
> if (!cxl_resource_contains_addr(p->res, hpa)) {
> dev_dbg(&cxlr->dev,
> "Addr trans fail: hpa 0x%llx not in region\n", hpa);
> @@ -3176,10 +3185,11 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
> struct cxl_region_params *p = &cxlr->params;
> struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
> struct cxl_endpoint_decoder *cxled;
> - u64 hpa, hpa_offset, dpa_offset;
> + u64 hpa_offset = offset;
> + u64 dpa_base, dpa_offset;
> u16 eig = 0;
> u8 eiw = 0;
> - int pos;
> + int pos = -1;
>
> lockdep_assert_held(&cxl_rwsem.region);
> lockdep_assert_held(&cxl_rwsem.dpa);
> @@ -3193,13 +3203,14 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
> * CXL HPA is assumed to equal SPA.
> */
> if (cxlrd->ops.spa_to_hpa) {
> - hpa = cxlrd->ops.spa_to_hpa(cxlrd, p->res->start + offset);
> - hpa_offset = hpa - p->res->start;
> - } else {
> - hpa_offset = offset;
> + hpa_offset = cxlrd->ops.spa_to_hpa(cxlrd, p->res->start + offset);
> + if (hpa_offset != ULLONG_MAX)
> + hpa_offset -= p->res->start;
> }
>
> - pos = cxl_calculate_position(hpa_offset, eiw, eig);
> + if (hpa_offset != ULLONG_MAX)
> + pos = cxl_calculate_position(hpa_offset, eiw, eig);
> +
> if (pos < 0 || pos >= p->nr_targets) {
> dev_dbg(&cxlr->dev, "Invalid position %d for %d targets\n",
> pos, p->nr_targets);
> @@ -3213,8 +3224,13 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
> cxled = p->targets[i];
> if (cxled->pos != pos)
> continue;
> +
> + dpa_base = cxl_dpa_resource_start(cxled);
> + if (dpa_base == ULLONG_MAX)
> + continue;
> +
> result->cxlmd = cxled_to_memdev(cxled);
> - result->dpa = cxl_dpa_resource_start(cxled) + dpa_offset;
> + result->dpa = dpa_base + dpa_offset;
>
> return 0;
> }
> diff --git a/tools/testing/cxl/test/cxl_translate.c b/tools/testing/cxl/test/cxl_translate.c
> index 2200ae21795c..66f8270aacd8 100644
> --- a/tools/testing/cxl/test/cxl_translate.c
> +++ b/tools/testing/cxl/test/cxl_translate.c
> @@ -69,7 +69,7 @@ static u64 to_hpa(u64 dpa_offset, int pos, u8 r_eiw, u16 r_eig, u8 hb_ways,
> /* Calculate base HPA offset from DPA and position */
> hpa_offset = cxl_calculate_hpa_offset(dpa_offset, pos, r_eiw, r_eig);
>
> - if (math == XOR_MATH) {
> + if (hpa_offset != ULLONG_MAX && math == XOR_MATH) {
> cximsd->nr_maps = hbiw_to_nr_maps[hb_ways];
> if (cximsd->nr_maps)
> return cxl_do_xormap_calc(cximsd, hpa_offset, hb_ways);
> @@ -262,7 +262,7 @@ static int test_random_params(void)
> reverse_dpa = cxl_calculate_dpa_offset(hpa, eiw, eig);
> reverse_pos = cxl_calculate_position(hpa, eiw, eig);
>
> - if (reverse_dpa != dpa || reverse_pos != pos) {
> + if (hpa == ULLONG_MAX || reverse_dpa != dpa || reverse_pos != pos) {
> pr_err("test random iter %d FAIL hpa=%llu, dpa=%llu reverse_dpa=%llu, pos=%d reverse_pos=%d eiw=%u eig=%u\n",
> i, hpa, dpa, reverse_dpa, pos, reverse_pos, eiw,
> eig);
> --
> 2.47.3
>
Hi Robert,
kernel test robot noticed the following build warnings:
[auto build test WARNING on ea5514e300568cbe8f19431c3e424d4791db8291]
url: https://github.com/intel-lab-lkp/linux/commits/Robert-Richter/cxl-region-Rename-misleading-variable-name-hpa-to-hpa_range/20251210-021858
base: ea5514e300568cbe8f19431c3e424d4791db8291
patch link: https://lore.kernel.org/r/20251209180659.208842-13-rrichter%40amd.com
patch subject: [PATCH v8 12/13] cxl: Check if ULLONG_MAX was returned from translation functions
config: i386-randconfig-003-20251215 (https://download.01.org/0day-ci/archive/20251215/202512150712.0PH2z2O5-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251215/202512150712.0PH2z2O5-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512150712.0PH2z2O5-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/cxl/core/hdm.c:533:25: warning: implicit conversion from 'unsigned long long' to 'resource_size_t' (aka 'unsigned int') changes value from 18446744073709551615 to 4294967295 [-Wconstant-conversion]
533 | resource_size_t base = ULLONG_MAX;
| ~~~~ ^~~~~~~~~~
include/vdso/limits.h:16:21: note: expanded from macro 'ULLONG_MAX'
16 | #define ULLONG_MAX (~0ULL)
| ^~~~~
1 warning generated.
vim +533 drivers/cxl/core/hdm.c
530
531 resource_size_t cxl_dpa_resource_start(struct cxl_endpoint_decoder *cxled)
532 {
> 533 resource_size_t base = ULLONG_MAX;
534
535 lockdep_assert_held(&cxl_rwsem.dpa);
536 if (cxled->dpa_res)
537 base = cxled->dpa_res->start;
538
539 return base;
540 }
541
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Robert,
kernel test robot noticed the following build warnings:
[auto build test WARNING on ea5514e300568cbe8f19431c3e424d4791db8291]
url: https://github.com/intel-lab-lkp/linux/commits/Robert-Richter/cxl-region-Rename-misleading-variable-name-hpa-to-hpa_range/20251210-021858
base: ea5514e300568cbe8f19431c3e424d4791db8291
patch link: https://lore.kernel.org/r/20251209180659.208842-13-rrichter%40amd.com
patch subject: [PATCH v8 12/13] cxl: Check if ULLONG_MAX was returned from translation functions
config: i386-randconfig-141-20251212 (https://download.01.org/0day-ci/archive/20251212/202512120346.aT9GKk20-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.4.0-5) 12.4.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251212/202512120346.aT9GKk20-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512120346.aT9GKk20-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from include/linux/limits.h:7,
from include/linux/overflow.h:6,
from include/linux/string.h:13,
from include/linux/seq_file.h:6,
from drivers/cxl/core/hdm.c:3:
drivers/cxl/core/hdm.c: In function 'cxl_dpa_resource_start':
>> include/vdso/limits.h:16:25: warning: conversion from 'long long unsigned int' to 'resource_size_t' {aka 'unsigned int'} changes value from '18446744073709551615' to '4294967295' [-Woverflow]
16 | #define ULLONG_MAX (~0ULL)
| ^
drivers/cxl/core/hdm.c:533:32: note: in expansion of macro 'ULLONG_MAX'
533 | resource_size_t base = ULLONG_MAX;
| ^~~~~~~~~~
vim +16 include/vdso/limits.h
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 4
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 5 #define USHRT_MAX ((unsigned short)~0U)
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 6 #define SHRT_MAX ((short)(USHRT_MAX >> 1))
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 7 #define SHRT_MIN ((short)(-SHRT_MAX - 1))
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 8 #define INT_MAX ((int)(~0U >> 1))
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 9 #define INT_MIN (-INT_MAX - 1)
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 10 #define UINT_MAX (~0U)
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 11 #define LONG_MAX ((long)(~0UL >> 1))
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 12 #define LONG_MIN (-LONG_MAX - 1)
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 13 #define ULONG_MAX (~0UL)
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 14 #define LLONG_MAX ((long long)(~0ULL >> 1))
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 15 #define LLONG_MIN (-LLONG_MAX - 1)
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 @16 #define ULLONG_MAX (~0ULL)
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 17 #define UINTPTR_MAX ULONG_MAX
3e0e9f8c6e3ca9 Vincenzo Frascino 2020-03-20 18
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On 12/9/25 11:06 AM, Robert Richter wrote:
> The return address of translation functions is not consistently
> checked for a valid address. Check if ULLONG_MAX was returned.
>
> Signed-off-by: Robert Richter <rrichter@amd.com>
> ---
> drivers/cxl/core/hdm.c | 2 +-
> drivers/cxl/core/region.c | 36 +++++++++++++++++++-------
> tools/testing/cxl/test/cxl_translate.c | 4 +--
> 3 files changed, 29 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 1c5d2022c87a..8b50cdce4b29 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -530,7 +530,7 @@ resource_size_t cxl_dpa_size(struct cxl_endpoint_decoder *cxled)
>
> resource_size_t cxl_dpa_resource_start(struct cxl_endpoint_decoder *cxled)
> {
> - resource_size_t base = -1;
> + resource_size_t base = ULLONG_MAX;
>
> lockdep_assert_held(&cxl_rwsem.dpa);
> if (cxled->dpa_res)
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index c7ac78f1b644..2c070c7c7bfe 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3124,7 +3124,7 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
> struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
> struct cxl_region_params *p = &cxlr->params;
> struct cxl_endpoint_decoder *cxled = NULL;
> - u64 dpa_offset, hpa_offset, hpa;
> + u64 base, dpa_offset, hpa_offset, hpa;
> u16 eig = 0;
> u8 eiw = 0;
> int pos;
> @@ -3142,8 +3142,14 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
> ways_to_eiw(p->interleave_ways, &eiw);
> granularity_to_eig(p->interleave_granularity, &eig);
>
> - dpa_offset = dpa - cxl_dpa_resource_start(cxled);
> + base = cxl_dpa_resource_start(cxled);
> + if (base == ULLONG_MAX)
> + return ULLONG_MAX;
> +
> + dpa_offset = dpa - base;
> hpa_offset = cxl_calculate_hpa_offset(dpa_offset, pos, eiw, eig);
> + if (hpa_offset == ULLONG_MAX)
> + return ULLONG_MAX;
>
> /* Apply the hpa_offset to the region base address */
> hpa = hpa_offset + p->res->start + p->cache_size;
> @@ -3152,6 +3158,9 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
> if (cxlrd->ops.hpa_to_spa)
> hpa = cxlrd->ops.hpa_to_spa(cxlrd, hpa);
>
> + if (hpa == ULLONG_MAX)
> + return ULLONG_MAX;
> +
> if (!cxl_resource_contains_addr(p->res, hpa)) {
> dev_dbg(&cxlr->dev,
> "Addr trans fail: hpa 0x%llx not in region\n", hpa);
> @@ -3176,10 +3185,11 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
> struct cxl_region_params *p = &cxlr->params;
> struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
> struct cxl_endpoint_decoder *cxled;
> - u64 hpa, hpa_offset, dpa_offset;
> + u64 hpa_offset = offset;
> + u64 dpa_base, dpa_offset;
> u16 eig = 0;
> u8 eiw = 0;
> - int pos;
> + int pos = -1;
>
> lockdep_assert_held(&cxl_rwsem.region);
> lockdep_assert_held(&cxl_rwsem.dpa);
> @@ -3193,13 +3203,14 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
> * CXL HPA is assumed to equal SPA.
> */
> if (cxlrd->ops.spa_to_hpa) {
> - hpa = cxlrd->ops.spa_to_hpa(cxlrd, p->res->start + offset);
> - hpa_offset = hpa - p->res->start;
> - } else {
> - hpa_offset = offset;
> + hpa_offset = cxlrd->ops.spa_to_hpa(cxlrd, p->res->start + offset);
> + if (hpa_offset != ULLONG_MAX)
Should it just return error here when hpa_offset == ULLONG_MAX?
> + hpa_offset -= p->res->start;
> }>
> - pos = cxl_calculate_position(hpa_offset, eiw, eig);
> + if (hpa_offset != ULLONG_MAX)
And this check won't be need if it returned earlier above
> + pos = cxl_calculate_position(hpa_offset, eiw, eig);
> +
> if (pos < 0 || pos >= p->nr_targets) {
> dev_dbg(&cxlr->dev, "Invalid position %d for %d targets\n",
> pos, p->nr_targets);
> @@ -3213,8 +3224,13 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
> cxled = p->targets[i];
> if (cxled->pos != pos)
> continue;
> +
> + dpa_base = cxl_dpa_resource_start(cxled);
> + if (dpa_base == ULLONG_MAX)
> + continue;
If dpa_base is ULLONG_MAX, should it be an error and exit instead of continuing?
DJ
> +
> result->cxlmd = cxled_to_memdev(cxled);
> - result->dpa = cxl_dpa_resource_start(cxled) + dpa_offset;
> + result->dpa = dpa_base + dpa_offset;
>
> return 0;
> }
> diff --git a/tools/testing/cxl/test/cxl_translate.c b/tools/testing/cxl/test/cxl_translate.c
> index 2200ae21795c..66f8270aacd8 100644
> --- a/tools/testing/cxl/test/cxl_translate.c
> +++ b/tools/testing/cxl/test/cxl_translate.c
> @@ -69,7 +69,7 @@ static u64 to_hpa(u64 dpa_offset, int pos, u8 r_eiw, u16 r_eig, u8 hb_ways,
> /* Calculate base HPA offset from DPA and position */
> hpa_offset = cxl_calculate_hpa_offset(dpa_offset, pos, r_eiw, r_eig);
>
> - if (math == XOR_MATH) {
> + if (hpa_offset != ULLONG_MAX && math == XOR_MATH) {
> cximsd->nr_maps = hbiw_to_nr_maps[hb_ways];
> if (cximsd->nr_maps)
> return cxl_do_xormap_calc(cximsd, hpa_offset, hb_ways);
> @@ -262,7 +262,7 @@ static int test_random_params(void)
> reverse_dpa = cxl_calculate_dpa_offset(hpa, eiw, eig);
> reverse_pos = cxl_calculate_position(hpa, eiw, eig);
>
> - if (reverse_dpa != dpa || reverse_pos != pos) {
> + if (hpa == ULLONG_MAX || reverse_dpa != dpa || reverse_pos != pos) {
> pr_err("test random iter %d FAIL hpa=%llu, dpa=%llu reverse_dpa=%llu, pos=%d reverse_pos=%d eiw=%u eig=%u\n",
> i, hpa, dpa, reverse_dpa, pos, reverse_pos, eiw,
> eig);
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