Thread (55 messages) 55 messages, 7 authors, 2021-09-27

Re: [PATCH v4 10/15] asm/io.h: Add ioremap_shared fallback

From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2021-08-12 19:46:44
Also in: linux-arch, linux-doc, linux-mips, linux-pci, lkml, sparclinux, virtualization

On Wed, Aug 04, 2021 at 05:52:13PM -0700, Kuppuswamy Sathyanarayanan wrote:
From: Andi Kleen <redacted>

This function is for declaring memory that should be shared with
a hypervisor in a confidential guest. If the architecture doesn't
implement it it's just ioremap.
I would assume ioremap_shared() would "map" something, not "declare"
it.
quoted hunk ↗ jump to hunk
Signed-off-by: Andi Kleen <redacted>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 arch/alpha/include/asm/io.h    | 1 +
 arch/mips/include/asm/io.h     | 1 +
 arch/parisc/include/asm/io.h   | 1 +
 arch/sparc/include/asm/io_64.h | 1 +
 include/asm-generic/io.h       | 4 ++++
 5 files changed, 8 insertions(+)
diff --git a/arch/alpha/include/asm/io.h b/arch/alpha/include/asm/io.h
index 0fab5ac90775..701b44909b94 100644
--- a/arch/alpha/include/asm/io.h
+++ b/arch/alpha/include/asm/io.h
@@ -283,6 +283,7 @@ static inline void __iomem *ioremap(unsigned long port, unsigned long size)
 }
 
 #define ioremap_wc ioremap
+#define ioremap_shared ioremap
 #define ioremap_uc ioremap
 
 static inline void iounmap(volatile void __iomem *addr)
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 6f5c86d2bab4..3713ff624632 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -179,6 +179,7 @@ void iounmap(const volatile void __iomem *addr);
 #define ioremap(offset, size)						\
 	ioremap_prot((offset), (size), _CACHE_UNCACHED)
 #define ioremap_uc		ioremap
+#define ioremap_shared		ioremap
 
 /*
  * ioremap_cache -	map bus memory into CPU space
diff --git a/arch/parisc/include/asm/io.h b/arch/parisc/include/asm/io.h
index 0b5259102319..73064e152df7 100644
--- a/arch/parisc/include/asm/io.h
+++ b/arch/parisc/include/asm/io.h
@@ -129,6 +129,7 @@ static inline void gsc_writeq(unsigned long long val, unsigned long addr)
  */
 void __iomem *ioremap(unsigned long offset, unsigned long size);
 #define ioremap_wc			ioremap
+#define ioremap_shared			ioremap
 #define ioremap_uc			ioremap
 
 extern void iounmap(const volatile void __iomem *addr);
diff --git a/arch/sparc/include/asm/io_64.h b/arch/sparc/include/asm/io_64.h
index 5ffa820dcd4d..18cc656eb712 100644
--- a/arch/sparc/include/asm/io_64.h
+++ b/arch/sparc/include/asm/io_64.h
@@ -409,6 +409,7 @@ static inline void __iomem *ioremap(unsigned long offset, unsigned long size)
 #define ioremap_uc(X,Y)			ioremap((X),(Y))
 #define ioremap_wc(X,Y)			ioremap((X),(Y))
 #define ioremap_wt(X,Y)			ioremap((X),(Y))
+#define ioremap_shared(X, Y)		ioremap((X), (Y))
 static inline void __iomem *ioremap_np(unsigned long offset, unsigned long size)
 {
 	return NULL;
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index e93375c710b9..bfcaee1691c8 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -982,6 +982,10 @@ static inline void __iomem *ioremap(phys_addr_t addr, size_t size)
 #define ioremap_wt ioremap
 #endif
 
+#ifndef ioremap_shared
+#define ioremap_shared ioremap
+#endif
"ioremap_shared" is a very generic term for a pretty specific thing:
"memory shared with a hypervisor in a confidential guest".

Maybe deserves a comment with at least a hint here.  "Hypervisors in a
confidential guest" isn't the first thing that comes to mind when I
read "shared".
 /*
  * ioremap_uc is special in that we do require an explicit architecture
  * implementation.  In general you do not want to use this function in a
-- 
2.25.1
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