arm/arm64: KVM: Map the HYP text as read-only

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 <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index f3320870a90af34b8e4e3fc5da6da4e1395c0af8..7487bf9f97dc4562c291e012f79916aebc81d9a3 100644 (file)
--- 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 b30897679e53c91e3e6264ab3f4a359bc77d7b97..c74483fc39f2c384f0d3702cf6fc047782332df4 100644 (file)
--- 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 49cb5ccf6c2377edd02ec1167af45bd98485d9bb..679608fa1666a7ac1437aed058ac52a5a92880b2 100644 (file)
--- 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 88db58cac5879e7a8b18a43e72a0389dc7d64fb9..380204847c20ed296f1c660519e28ddd14385e00 100644 (file)
--- 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)