[PATCH 04/55] arm/arm64: KVM: Map the HYP text as read-only
From: Marc Zyngier <hidden>
Date: 2016-07-22 17:28:21
Also in:
kvm, kvmarm
Subsystem:
arm port, arm64 port (aarch64 architecture), the rest · Maintainers:
Russell King, Catalin Marinas, Will Deacon, Linus Torvalds
There should be no reason for mapping the HYP text read/write. As such, let's have a new set of flags (PAGE_HYP_EXEC) that allows execution, but makes the page as read-only, and update the two call sites that deal with mapping code. Signed-off-by: Marc Zyngier <redacted> Signed-off-by: Christoffer Dall <redacted> --- arch/arm/include/asm/pgtable.h | 1 + arch/arm/kvm/arm.c | 2 +- arch/arm/kvm/mmu.c | 6 +++--- arch/arm64/include/asm/pgtable-prot.h | 1 + 4 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index f332087..7487bf9 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h@@ -98,6 +98,7 @@ extern pgprot_t pgprot_s2_device; #define PAGE_KERNEL _MOD_PROT(pgprot_kernel, L_PTE_XN) #define PAGE_KERNEL_EXEC pgprot_kernel #define PAGE_HYP _MOD_PROT(pgprot_kernel, L_PTE_HYP) +#define PAGE_HYP_EXEC _MOD_PROT(pgprot_kernel, L_PTE_HYP | L_PTE_RDONLY) #define PAGE_HYP_RO _MOD_PROT(pgprot_kernel, L_PTE_HYP | L_PTE_RDONLY | L_PTE_XN) #define PAGE_HYP_DEVICE _MOD_PROT(pgprot_hyp_device, L_PTE_HYP) #define PAGE_S2 _MOD_PROT(pgprot_s2, L_PTE_S2_RDONLY)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index b308976..c74483f 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c@@ -1293,7 +1293,7 @@ static int init_hyp_mode(void) * Map the Hyp-code called directly from the host */ err = create_hyp_mappings(kvm_ksym_ref(__hyp_text_start), - kvm_ksym_ref(__hyp_text_end), PAGE_HYP); + kvm_ksym_ref(__hyp_text_end), PAGE_HYP_EXEC); if (err) { kvm_err("Cannot map world-switch code\n"); goto out_err;
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 49cb5cc..679608f 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c@@ -1733,7 +1733,7 @@ int kvm_mmu_init(void) err = __create_hyp_mappings(boot_hyp_pgd, hyp_idmap_start, hyp_idmap_end, __phys_to_pfn(hyp_idmap_start), - PAGE_HYP); + PAGE_HYP_EXEC); if (err) { kvm_err("Failed to idmap %lx-%lx\n",
@@ -1756,7 +1756,7 @@ int kvm_mmu_init(void) err = __create_hyp_mappings(boot_hyp_pgd, TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE, __phys_to_pfn(hyp_idmap_start), - PAGE_HYP); + PAGE_HYP_EXEC); if (err) { kvm_err("Failed to map trampoline @%lx into boot HYP pgd\n", TRAMPOLINE_VA);
@@ -1767,7 +1767,7 @@ int kvm_mmu_init(void) err = __create_hyp_mappings(hyp_pgd, TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE, __phys_to_pfn(hyp_idmap_start), - PAGE_HYP); + PAGE_HYP_EXEC); if (err) { kvm_err("Failed to map trampoline @%lx into runtime HYP pgd\n", TRAMPOLINE_VA);
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 88db58c..3802048 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h@@ -56,6 +56,7 @@ #define PAGE_KERNEL_EXEC_CONT __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_CONT) #define PAGE_HYP __pgprot(_PAGE_DEFAULT | PTE_HYP) +#define PAGE_HYP_EXEC __pgprot(_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY) #define PAGE_HYP_RO __pgprot(_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN) #define PAGE_HYP_DEVICE __pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
--
2.8.1