[PATCH kvm-unit-tests v3 4/8] arm/arm64: mmu: Stop mapping an assumed IO region

[Andrew Jones <drjones@redhat.com>]

By providing a proper ioremap function, we can just rely on devices
calling it for each region they need (as they already do) instead of
mapping a big assumed I/O range. We don't require the MMU to be
enabled at the time of the ioremap. In that case, we add the mapping
to the identity map anyway. This allows us to call setup_vm after
io_init. Why don't we just call setup_vm before io_init, I hear you
ask? Well, that's because tests like sieve want to start with the MMU
off, later call setup_vm, and all the while have working I/O. Some
unit tests are just really demanding...

While at it, ensure we map the I/O regions with XN (execute never),
as suggested by Alexandru Elisei.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 lib/arm/asm/io.h            |  6 ++++++
 lib/arm/asm/mmu.h           |  3 +++
 lib/arm/asm/page.h          |  2 ++
 lib/arm/asm/pgtable-hwdef.h |  1 +
 lib/arm/mmu.c               | 37 +++++++++++++++++++++++++++----------
 lib/arm64/asm/io.h          |  6 ++++++
 lib/arm64/asm/mmu.h         |  1 +
 lib/arm64/asm/page.h        |  2 ++
 8 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/lib/arm/asm/io.h b/lib/arm/asm/io.h
index ba3b0b2412ad..e4caa6ff5d1e 100644
--- a/lib/arm/asm/io.h
+++ b/lib/arm/asm/io.h
@@ -77,6 +77,12 @@ static inline void __raw_writel(u32 val, volatile void __iomem *addr)
 		     : "r" (val));
 }
 
+#define ioremap ioremap
+static inline void __iomem *ioremap(phys_addr_t phys_addr, size_t size)
+{
+	return __ioremap(phys_addr, size);
+}
+
 #define virt_to_phys virt_to_phys
 static inline phys_addr_t virt_to_phys(const volatile void *x)
 {
diff --git a/lib/arm/asm/mmu.h b/lib/arm/asm/mmu.h
index 122874b8aebe..94e70f0a84bf 100644
--- a/lib/arm/asm/mmu.h
+++ b/lib/arm/asm/mmu.h
@@ -8,10 +8,13 @@
 #include <asm/barrier.h>
 
 #define PTE_USER		L_PTE_USER
+#define PTE_UXN			L_PTE_XN
+#define PTE_PXN			L_PTE_PXN
 #define PTE_RDONLY		PTE_AP2
 #define PTE_SHARED		L_PTE_SHARED
 #define PTE_AF			PTE_EXT_AF
 #define PTE_WBWA		L_PTE_MT_WRITEALLOC
+#define PTE_UNCACHED		L_PTE_MT_UNCACHED
 
 /* See B3.18.7 TLB maintenance operations */
 
diff --git a/lib/arm/asm/page.h b/lib/arm/asm/page.h
index 1fb5cd26ac66..8eb4a883808e 100644
--- a/lib/arm/asm/page.h
+++ b/lib/arm/asm/page.h
@@ -47,5 +47,7 @@ typedef struct { pteval_t pgprot; } pgprot_t;
 extern phys_addr_t __virt_to_phys(unsigned long addr);
 extern unsigned long __phys_to_virt(phys_addr_t addr);
 
+extern void *__ioremap(phys_addr_t phys_addr, size_t size);
+
 #endif /* !__ASSEMBLY__ */
 #endif /* _ASMARM_PAGE_H_ */
diff --git a/lib/arm/asm/pgtable-hwdef.h b/lib/arm/asm/pgtable-hwdef.h
index fe1d8540ea3f..90fd306c7cc0 100644
--- a/lib/arm/asm/pgtable-hwdef.h
+++ b/lib/arm/asm/pgtable-hwdef.h
@@ -34,6 +34,7 @@
 #define L_PTE_USER		(_AT(pteval_t, 1) << 6)		/* AP[1] */
 #define L_PTE_SHARED		(_AT(pteval_t, 3) << 8)		/* SH[1:0], inner shareable */
 #define L_PTE_YOUNG		(_AT(pteval_t, 1) << 10)	/* AF */
+#define L_PTE_PXN		(_AT(pteval_t, 1) << 53)	/* PXN */
 #define L_PTE_XN		(_AT(pteval_t, 1) << 54)	/* XN */
 
 /*
diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c
index 15eef007f256..791b1f88f946 100644
--- a/lib/arm/mmu.c
+++ b/lib/arm/mmu.c
@@ -11,6 +11,7 @@
 #include <asm/mmu.h>
 #include <asm/setup.h>
 #include <asm/page.h>
+#include <asm/io.h>
 
 #include "alloc_page.h"
 #include "vmalloc.h"
@@ -157,9 +158,8 @@ void mmu_set_range_sect(pgd_t *pgtable, uintptr_t virt_offset,
 void *setup_mmu(phys_addr_t phys_end)
 {
 	uintptr_t code_end = (uintptr_t)&etext;
-	struct mem_region *r;
 
-	/* 0G-1G = I/O, 1G-3G = identity, 3G-4G = vmalloc */
+	/* 3G-4G region is reserved for vmalloc, cap phys_end at 3G */
 	if (phys_end > (3ul << 30))
 		phys_end = 3ul << 30;
 
@@ -170,14 +170,8 @@ void *setup_mmu(phys_addr_t phys_end)
 			"Unsupported translation granule %ld\n", PAGE_SIZE);
 #endif
 
-	mmu_idmap = alloc_page();
-
-	for (r = mem_regions; r->end; ++r) {
-		if (!(r->flags & MR_F_IO))
-			continue;
-		mmu_set_range_sect(mmu_idmap, r->start, r->start, r->end,
-				   __pgprot(PMD_SECT_UNCACHED | PMD_SECT_USER));
-	}
+	if (!mmu_idmap)
+		mmu_idmap = alloc_page();
 
 	/* armv8 requires code shared between EL1 and EL0 to be read-only */
 	mmu_set_range_ptes(mmu_idmap, PHYS_OFFSET,
@@ -192,6 +186,29 @@ void *setup_mmu(phys_addr_t phys_end)
 	return mmu_idmap;
 }
 
+void __iomem *__ioremap(phys_addr_t phys_addr, size_t size)
+{
+	phys_addr_t paddr_aligned = phys_addr & PAGE_MASK;
+	phys_addr_t paddr_end = PAGE_ALIGN(phys_addr + size);
+	pgprot_t prot = __pgprot(PTE_UNCACHED | PTE_USER | PTE_UXN | PTE_PXN);
+	pgd_t *pgtable;
+
+	assert(sizeof(long) == 8 || !(phys_addr >> 32));
+
+	if (mmu_enabled()) {
+		pgtable = current_thread_info()->pgtable;
+	} else {
+		if (!mmu_idmap)
+			mmu_idmap = alloc_page();
+		pgtable = mmu_idmap;
+	}
+
+	mmu_set_range_ptes(pgtable, paddr_aligned, paddr_aligned,
+			   paddr_end, prot);
+
+	return (void __iomem *)(unsigned long)phys_addr;
+}
+
 phys_addr_t __virt_to_phys(unsigned long addr)
 {
 	if (mmu_enabled()) {
diff --git a/lib/arm64/asm/io.h b/lib/arm64/asm/io.h
index e0a03b250d5b..be19f471c0fa 100644
--- a/lib/arm64/asm/io.h
+++ b/lib/arm64/asm/io.h
@@ -71,6 +71,12 @@ static inline u64 __raw_readq(const volatile void __iomem *addr)
 	return val;
 }
 
+#define ioremap ioremap
+static inline void __iomem *ioremap(phys_addr_t phys_addr, size_t size)
+{
+	return __ioremap(phys_addr, size);
+}
+
 #define virt_to_phys virt_to_phys
 static inline phys_addr_t virt_to_phys(const volatile void *x)
 {
diff --git a/lib/arm64/asm/mmu.h b/lib/arm64/asm/mmu.h
index 72d75eafc882..72371b2d9fe3 100644
--- a/lib/arm64/asm/mmu.h
+++ b/lib/arm64/asm/mmu.h
@@ -8,6 +8,7 @@
 #include <asm/barrier.h>
 
 #define PMD_SECT_UNCACHED	PMD_ATTRINDX(MT_DEVICE_nGnRE)
+#define PTE_UNCACHED		PTE_ATTRINDX(MT_DEVICE_nGnRE)
 #define PTE_WBWA		PTE_ATTRINDX(MT_NORMAL)
 
 static inline void flush_tlb_all(void)
diff --git a/lib/arm64/asm/page.h b/lib/arm64/asm/page.h
index ae4484b22114..d0fac6ea563d 100644
--- a/lib/arm64/asm/page.h
+++ b/lib/arm64/asm/page.h
@@ -72,5 +72,7 @@ typedef struct { pteval_t pgprot; } pgprot_t;
 extern phys_addr_t __virt_to_phys(unsigned long addr);
 extern unsigned long __phys_to_virt(phys_addr_t addr);
 
+extern void *__ioremap(phys_addr_t phys_addr, size_t size);
+
 #endif /* !__ASSEMBLY__ */
 #endif /* _ASMARM64_PAGE_H_ */
-- 
2.30.2