From: Tianyu Lan <Tianyu.Lan@microsoft.com>

HAS_IOMEM option may not be selected on some platforms(e.g, s390) and this
will cause compile error due to miss memremap() implementation. Fix it via
adding HAS_IOMEM check around memremap() in the swiotlb.c.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 kernel/dma/swiotlb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index b36c1cdd0c4f..3de651ba38cc 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -167,6 +167,7 @@ static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
 {
 	void *vaddr = NULL;
 
+#ifdef CONFIG_HAS_IOMEM
 	if (swiotlb_unencrypted_base) {
 		phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
 
@@ -175,6 +176,7 @@ static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
 			pr_err("Failed to map the unencrypted memory %pa size %lx.\n",
 			       &paddr, bytes);
 	}
+#endif
 
 	return vaddr;
 }
-- 
2.25.1

On Fri, Dec 31, 2021 at 11:56:40AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> HAS_IOMEM option may not be selected on some platforms(e.g, s390) and this
> will cause compile error due to miss memremap() implementation. Fix it via

miss -> missingk

> adding HAS_IOMEM check around memremap() in the swiotlb.c.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>

Hi Christoph

Are you happy with this fix?

Thanks,
Wei.

> ---
>  kernel/dma/swiotlb.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index b36c1cdd0c4f..3de651ba38cc 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -167,6 +167,7 @@ static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
>  {
>  	void *vaddr = NULL;
>  
> +#ifdef CONFIG_HAS_IOMEM
>  	if (swiotlb_unencrypted_base) {
>  		phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
>  
> @@ -175,6 +176,7 @@ static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
>  			pr_err("Failed to map the unencrypted memory %pa size %lx.\n",
>  			       &paddr, bytes);
>  	}
> +#endif
>  
>  	return vaddr;
>  }
> -- 
> 2.25.1
> 

On Fri, Dec 31, 2021 at 11:56:40AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> HAS_IOMEM option may not be selected on some platforms(e.g, s390) and this
> will cause compile error due to miss memremap() implementation. Fix it via
> adding HAS_IOMEM check around memremap() in the swiotlb.c.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> ---
>  kernel/dma/swiotlb.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index b36c1cdd0c4f..3de651ba38cc 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -167,6 +167,7 @@ static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
>  {
>  	void *vaddr = NULL;
>  
> +#ifdef CONFIG_HAS_IOMEM

Please stub out all of swiotlb_mem_remap instead of the ifdef inside the
function.

On Sun, Jan 02, 2022 at 11:54:46PM -0800, Christoph Hellwig wrote:
> On Fri, Dec 31, 2021 at 11:56:40AM -0500, Tianyu Lan wrote:
> > From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> > 
> > HAS_IOMEM option may not be selected on some platforms(e.g, s390) and this
> > will cause compile error due to miss memremap() implementation. Fix it via
> > adding HAS_IOMEM check around memremap() in the swiotlb.c.
> > 
> > Reported-by: kernel test robot <lkp@intel.com>
> > Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> > ---
> >  kernel/dma/swiotlb.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> > index b36c1cdd0c4f..3de651ba38cc 100644
> > --- a/kernel/dma/swiotlb.c
> > +++ b/kernel/dma/swiotlb.c
> > @@ -167,6 +167,7 @@ static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
> >  {
> >  	void *vaddr = NULL;
> >  
> > +#ifdef CONFIG_HAS_IOMEM
> 
> Please stub out all of swiotlb_mem_remap instead of the ifdef inside the
> function.

Does this look okay to you?

---8<---
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index b36c1cdd0c4f..f1e7ea160b43 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -163,6 +163,7 @@ static inline unsigned long nr_slots(u64 val)
  * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP
  * Isolation VMs).
  */
+#ifdef CONFIG_HAS_IOMEM
 static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
 {
 	void *vaddr = NULL;
@@ -178,6 +179,12 @@ static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
 
 	return vaddr;
 }
+#else
+static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
+{
+	return NULL;
+}
+#endif
 
 /*
  * Early SWIOTLB allocation may be too early to allow an architecture to

On Tue, Jan 04, 2022 at 02:51:55PM +0000, Wei Liu wrote:
> > Please stub out all of swiotlb_mem_remap instead of the ifdef inside the
> > function.
> 
> Does this look okay to you?

Yes, thanks!

On Tue, Jan 04, 2022 at 04:03:07PM +0100, Christoph Hellwig wrote:
> On Tue, Jan 04, 2022 at 02:51:55PM +0000, Wei Liu wrote:
> > > Please stub out all of swiotlb_mem_remap instead of the ifdef inside the
> > > function.
> > 
> > Does this look okay to you?
> 
> Yes, thanks!

Thanks for confirming!

I will turn this into an ack and apply the diff to hyperv-next.

Wei.