From: Christoffer Dall <cdall@xxxxxxxxxxxxxxx>
Adds support in the identity mapping feature that allows KVM to setup
identity mapping for the Hyp mode with the AP[1] bit set as required by
the specification and also supports freeing created sub pmd's after
finished use.
These two functions:
- hyp_identity_mapping_add(pgd, addr, end);
- hyp_identity_mapping_del(pgd, addr, end);
are essentially calls to the same function as the non-hyp versions but
with a different argument value. KVM calls these functions to setup
and teardown the identity mapping used to initialize the hypervisor.
Note, the hyp-version of the _del function actually frees the pmd's
pointed to by the pgd as opposed to the non-hyp version which just
clears them.
Signed-off-by: Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx>
---
arch/arm/include/asm/pgtable-3level-hwdef.h | 1 +
arch/arm/include/asm/pgtable.h | 6 +++
arch/arm/mm/idmap.c | 54 +++++++++++++++++++++++++++
3 files changed, 60 insertions(+), 1 deletions(-)
diff --git a/arch/arm/include/asm/pgtable-3level-hwdef.h b/arch/arm/include/asm/pgtable-3level-hwdef.h
index d795282..a2d404e 100644
--- a/arch/arm/include/asm/pgtable-3level-hwdef.h
+++ b/arch/arm/include/asm/pgtable-3level-hwdef.h
@@ -44,6 +44,7 @@
#define PMD_SECT_XN (_AT(pmdval_t, 1) << 54)
#define PMD_SECT_AP_WRITE (_AT(pmdval_t, 0))
#define PMD_SECT_AP_READ (_AT(pmdval_t, 0))
+#define PMD_SECT_AP1 (_AT(pmdval_t, 1) << 6)
#define PMD_SECT_TEX(x) (_AT(pmdval_t, 0))
/*
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index aec18ab..19456f4 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -318,6 +318,12 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
void identity_mapping_add(pgd_t *, unsigned long, unsigned long);
void identity_mapping_del(pgd_t *, unsigned long, unsigned long);
+#ifdef CONFIG_KVM_ARM_HOST
+void hyp_identity_mapping_add(pgd_t *, unsigned long, unsigned long);
+void hyp_identity_mapping_del(pgd_t *pgd, unsigned long addr,
+ unsigned long end);
+#endif
+
#endif /* !__ASSEMBLY__ */
#endif /* CONFIG_MMU */
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index 267db72..e29903a 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -1,3 +1,4 @@
+#include <linux/module.h>
#include <linux/kernel.h>
#include <asm/cputype.h>
@@ -54,11 +55,18 @@ static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
} while (pud++, addr = next, addr != end);
}
-void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
+static void __identity_mapping_add(pgd_t *pgd, unsigned long addr,
+ unsigned long end, bool hyp_mapping)
{
unsigned long prot, next;
prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
+
+#ifdef CONFIG_ARM_LPAE
+ if (hyp_mapping)
+ prot |= PMD_SECT_AP1;
+#endif
+
if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
prot |= PMD_BIT4;
@@ -69,6 +77,12 @@ void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
} while (pgd++, addr = next, addr != end);
}
+void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
+{
+ __identity_mapping_add(pgd, addr, end, false);
+}
+
+
#ifdef CONFIG_SMP
static void idmap_del_pmd(pud_t *pud, unsigned long addr, unsigned long end)
{
@@ -103,6 +117,44 @@ void identity_mapping_del(pgd_t *pgd, unsigned long addr, unsigned long end)
}
#endif
+#ifdef CONFIG_KVM_ARM_HOST
+void hyp_identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
+{
+ __identity_mapping_add(pgd, addr, end, true);
+}
+EXPORT_SYMBOL_GPL(hyp_identity_mapping_add);
+
+static void hyp_idmap_del_pmd(pgd_t *pgd, unsigned long addr)
+{
+ pud_t *pud;
+ pmd_t *pmd;
+
+ pud = pud_offset(pgd, addr);
+ pmd = pmd_offset(pud, addr);
+ pmd_free(NULL, pmd);
+}
+
+/*
+ * This version actually frees the underlying pmds for all pgds in range and
+ * clear the pgds themselves afterwards.
+ */
+void hyp_identity_mapping_del(pgd_t *pgd, unsigned long addr, unsigned long end)
+{
+ unsigned long next;
+ pgd_t *next_pgd;
+
+ do {
+ next = pgd_addr_end(addr, end);
+ next_pgd = pgd + pgd_index(addr);
+ if (!pgd_none_or_clear_bad(next_pgd)) {
+ hyp_idmap_del_pmd(next_pgd, addr);
+ pgd_clear(next_pgd);
+ }
+ } while (addr = next, addr < end);
+}
+EXPORT_SYMBOL_GPL(hyp_identity_mapping_del);
+#endif
+
/*
* In order to soft-boot, we need to insert a 1:1 mapping in place of
* the user-mode pages. This will then ensure that we have predictable
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