On 7/1/24 7:54 PM, Steven Price wrote:
All I/O is by default considered non-secure for realms. As such
mark them as shared with the host.
Co-developed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
Changes since v3:
* Add PROT_NS_SHARED to FIXMAP_PAGE_IO rather than overriding
set_fixmap_io() with a custom function.
* Modify ioreamp_cache() to specify PROT_NS_SHARED too.
---
arch/arm64/include/asm/fixmap.h | 2 +-
arch/arm64/include/asm/io.h | 8 ++++----
2 files changed, 5 insertions(+), 5 deletions(-)
I'm unable to understand this. Steven, could you please explain a bit how
PROT_NS_SHARED is turned to a shared (non-secure) mapping to hardware?
According to tf-rmm's implementation in tf-rmm/lib/s2tt/src/s2tt_pvt_defs.h,
a shared (non-secure) mapping is is identified by NS bit (bit#55). I find
difficulties how the NS bit is correlate with PROT_NS_SHARED. For example,
how the NS bit is set based on PROT_NS_SHARED.
diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 87e307804b99..f2c5e653562e 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -98,7 +98,7 @@ enum fixed_addresses {
#define FIXADDR_TOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_TOT_START (FIXADDR_TOP - FIXADDR_TOT_SIZE)
-#define FIXMAP_PAGE_IO __pgprot(PROT_DEVICE_nGnRE)
+#define FIXMAP_PAGE_IO __pgprot(PROT_DEVICE_nGnRE | PROT_NS_SHARED)
void __init early_fixmap_init(void);
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 4ff0ae3f6d66..07fc1801c6ad 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -277,12 +277,12 @@ static inline void __const_iowrite64_copy(void __iomem *to, const void *from,
#define ioremap_prot ioremap_prot
-#define _PAGE_IOREMAP PROT_DEVICE_nGnRE
+#define _PAGE_IOREMAP (PROT_DEVICE_nGnRE | PROT_NS_SHARED)
#define ioremap_wc(addr, size) \
- ioremap_prot((addr), (size), PROT_NORMAL_NC)
+ ioremap_prot((addr), (size), (PROT_NORMAL_NC | PROT_NS_SHARED))
#define ioremap_np(addr, size) \
- ioremap_prot((addr), (size), PROT_DEVICE_nGnRnE)
+ ioremap_prot((addr), (size), (PROT_DEVICE_nGnRnE | PROT_NS_SHARED))
/*
* io{read,write}{16,32,64}be() macros
@@ -303,7 +303,7 @@ static inline void __iomem *ioremap_cache(phys_addr_t addr, size_t size)
if (pfn_is_map_memory(__phys_to_pfn(addr)))
return (void __iomem *)__phys_to_virt(addr);
- return ioremap_prot(addr, size, PROT_NORMAL);
+ return ioremap_prot(addr, size, PROT_NORMAL | PROT_NS_SHARED);
}
/*
Thanks,
Gavin
