This patch fixes two sparse warnings
1. sparse complaining about the removal of __iomem address
space when casting the return value of this ioremap_cache(...)
from `void __ioremap*` to `void*`.
Fixed this by replacing the ioremap_cache(...)
by memremap(...) and using MEMREMAP_DEC and MEMREMAP_WB flag for making
sure the memory is always decrypted and it will support full write back
cache.
2. sparse complaining `expected void volatile [noderef] __iomem *addr`
when calling iounmap with a non __iomem pointer.
Fixed this by replacing iounmap(...) with memumap(...).
Signed-off-by: Abhinav Singh <[email protected]>
---
v1:
https://lore.kernel.org/all/[email protected]/T/
v1 to v2:
1. Fixed the comment which was earlier describing ioremap_cache(...).
2. Replaced iounmap(...) with memremap(...) inside function hv_cpu_die(...).
arch/x86/hyperv/hv_init.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 21556ad87f4b..2a14928b8a36 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -68,9 +68,11 @@ static int hyperv_init_ghcb(void)
*/
rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
- /* Mask out vTOM bit. ioremap_cache() maps decrypted */
+ /* Mask out vTOM bit.
+ MEMREMAP_WB full write back cache
+ MEMREMAP_DEC maps decrypted memory */
ghcb_gpa &= ~ms_hyperv.shared_gpa_boundary;
- ghcb_va = (void *)ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
+ ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB | MEMREMAP_DEC);
if (!ghcb_va)
return -ENOMEM;
@@ -238,7 +240,7 @@ static int hv_cpu_die(unsigned int cpu)
if (hv_ghcb_pg) {
ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
if (*ghcb_va)
- iounmap(*ghcb_va);
+ memunmap(*ghcb_va);
*ghcb_va = NULL;
}
--
2.39.2
From: Abhinav Singh <[email protected]> Sent: Monday, October 30, 2023 3:50 PM
>
> This patch fixes two sparse warnings
>
> 1. sparse complaining about the removal of __iomem address
> space when casting the return value of this ioremap_cache(...)
> from `void __ioremap*` to `void*`.
> Fixed this by replacing the ioremap_cache(...)
> by memremap(...) and using MEMREMAP_DEC and MEMREMAP_WB flag for
> making
> sure the memory is always decrypted and it will support full write back
> cache.
>
> 2. sparse complaining `expected void volatile [noderef] __iomem *addr`
> when calling iounmap with a non __iomem pointer.
> Fixed this by replacing iounmap(...) with memumap(...).
>
> Signed-off-by: Abhinav Singh <[email protected]>
Since Nischala has posted her more comprehensive patch,
this patch can be dropped. But see one comment below for
future reference.
> ---
>
> v1:
> https://lore.kernel.org/all/[email protected]/T/
>
> v1 to v2:
> 1. Fixed the comment which was earlier describing ioremap_cache(...).
> 2. Replaced iounmap(...) with memremap(...) inside function hv_cpu_die(...).
>
> arch/x86/hyperv/hv_init.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index 21556ad87f4b..2a14928b8a36 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -68,9 +68,11 @@ static int hyperv_init_ghcb(void)
> */
> rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
>
> - /* Mask out vTOM bit. ioremap_cache() maps decrypted */
> + /* Mask out vTOM bit.
> + MEMREMAP_WB full write back cache
> + MEMREMAP_DEC maps decrypted memory */
This isn't the right style for multi-line patches. Correct would be:
/*
* Mask out vTOM bit.
* MEMREMAP_WB full write back cache
* MEMREMAP_DEC maps decrypted memory
*/
Section 8 of coding-style.rst under Documentation/process covers
these details. Note that the style is slightly different for code
under net and drivers/net.
Michael
> ghcb_gpa &= ~ms_hyperv.shared_gpa_boundary;
> - ghcb_va = (void *)ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
> + ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB | MEMREMAP_DEC);
> if (!ghcb_va)
> return -ENOMEM;
>
> @@ -238,7 +240,7 @@ static int hv_cpu_die(unsigned int cpu)
> if (hv_ghcb_pg) {
> ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
> if (*ghcb_va)
> - iounmap(*ghcb_va);
> + memunmap(*ghcb_va);
> *ghcb_va = NULL;
> }
>
> --
> 2.39.2
On 11/5/23 20:55, Michael Kelley wrote:
> From: Abhinav Singh <[email protected]> Sent: Monday, October 30, 2023 3:50 PM
>>
>> This patch fixes two sparse warnings
>>
>> 1. sparse complaining about the removal of __iomem address
>> space when casting the return value of this ioremap_cache(...)
>> from `void __ioremap*` to `void*`.
>> Fixed this by replacing the ioremap_cache(...)
>> by memremap(...) and using MEMREMAP_DEC and MEMREMAP_WB flag for
>> making
>> sure the memory is always decrypted and it will support full write back
>> cache.
>>
>> 2. sparse complaining `expected void volatile [noderef] __iomem *addr`
>> when calling iounmap with a non __iomem pointer.
>> Fixed this by replacing iounmap(...) with memumap(...).
>>
>> Signed-off-by: Abhinav Singh <[email protected]>
>
> Since Nischala has posted her more comprehensive patch,
> this patch can be dropped. But see one comment below for
> future reference.
>
>> ---
>>
>> v1:
>> https://lore.kernel.org/all/[email protected]/T/
>>
>> v1 to v2:
>> 1. Fixed the comment which was earlier describing ioremap_cache(...).
>> 2. Replaced iounmap(...) with memremap(...) inside function hv_cpu_die(...).
>>
>> arch/x86/hyperv/hv_init.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
>> index 21556ad87f4b..2a14928b8a36 100644
>> --- a/arch/x86/hyperv/hv_init.c
>> +++ b/arch/x86/hyperv/hv_init.c
>> @@ -68,9 +68,11 @@ static int hyperv_init_ghcb(void)
>> */
>> rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
>>
>> - /* Mask out vTOM bit. ioremap_cache() maps decrypted */
>> + /* Mask out vTOM bit.
>> + MEMREMAP_WB full write back cache
>> + MEMREMAP_DEC maps decrypted memory */
>
> This isn't the right style for multi-line patches. Correct would be:
>
> /*
> * Mask out vTOM bit.
> * MEMREMAP_WB full write back cache
> * MEMREMAP_DEC maps decrypted memory
> */
>
> Section 8 of coding-style.rst under Documentation/process covers
> these details. Note that the style is slightly different for code
> under net and drivers/net.
>
> Michael
>
>> ghcb_gpa &= ~ms_hyperv.shared_gpa_boundary;
>> - ghcb_va = (void *)ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
>> + ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB | MEMREMAP_DEC);
>> if (!ghcb_va)
>> return -ENOMEM;
>>
>> @@ -238,7 +240,7 @@ static int hv_cpu_die(unsigned int cpu)
>> if (hv_ghcb_pg) {
>> ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
>> if (*ghcb_va)
>> - iounmap(*ghcb_va);
>> + memunmap(*ghcb_va);
>> *ghcb_va = NULL;
>> }
>>
>> --
>> 2.39.2
>
Thanks a lot for taking a look and the suggestion, will keep this in
mind in future patches.
Thanks,
Abhinav