Actually, what do you think of this one:
---
>From a5ee278f4244c6bfc0ce2d2b2fd4f99358dbde4d Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Tue, 16 Jun 2020 11:50:59 +0200
Subject: x86/hyperv: allocate the hypercall page with only read and execute
bits
Avoid a W^X violation cause by the fact that PAGE_KERNEL_EXEC includes the
writable bit.
Fixes: 78bb17f76edc ("x86/hyperv: use vmalloc_exec for the hypercall page")
Reported-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/x86/hyperv/hv_init.c | 4 +++-
arch/x86/include/asm/pgtable_types.h | 2 ++
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index a54c6a401581dd..f4875bf05c17ff 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -375,7 +375,9 @@ void __init hyperv_init(void)
guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
- hv_hypercall_pg = vmalloc_exec(PAGE_SIZE);
+ hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,
+ VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_RX,
+ VM_FLUSH_RESET_PERMS, NUMA_NO_NODE, __func__);
if (hv_hypercall_pg == NULL) {
wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
goto remove_cpuhp_state;
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 2da1f95b88d761..591b5c92a66249 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -194,6 +194,7 @@ enum page_cache_mode {
#define _PAGE_TABLE_NOENC (__PP|__RW|_USR|___A| 0|___D| 0| 0)
#define _PAGE_TABLE (__PP|__RW|_USR|___A| 0|___D| 0| 0| _ENC)
#define __PAGE_KERNEL_RO (__PP| 0| 0|___A|__NX|___D| 0|___G)
+#define __PAGE_KERNEL_RX (__PP| 0| 0|___A| 0|___D| 0|___G)
#define __PAGE_KERNEL_NOCACHE (__PP|__RW| 0|___A|__NX|___D| 0|___G| __NC)
#define __PAGE_KERNEL_VVAR (__PP| 0|_USR|___A|__NX|___D| 0|___G)
#define __PAGE_KERNEL_LARGE (__PP|__RW| 0|___A|__NX|___D|_PSE|___G)
@@ -219,6 +220,7 @@ enum page_cache_mode {
#define PAGE_KERNEL_RO __pgprot_mask(__PAGE_KERNEL_RO | _ENC)
#define PAGE_KERNEL_EXEC __pgprot_mask(__PAGE_KERNEL_EXEC | _ENC)
#define PAGE_KERNEL_EXEC_NOENC __pgprot_mask(__PAGE_KERNEL_EXEC | 0)
+#define PAGE_KERNEL_RX __pgprot_mask(__PAGE_KERNEL_RX | _ENC)
#define PAGE_KERNEL_NOCACHE __pgprot_mask(__PAGE_KERNEL_NOCACHE | _ENC)
#define PAGE_KERNEL_LARGE __pgprot_mask(__PAGE_KERNEL_LARGE | _ENC)
#define PAGE_KERNEL_LARGE_EXEC __pgprot_mask(__PAGE_KERNEL_LARGE_EXEC | _ENC)
--
2.26.2
