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From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Dexuan Cui <decui@microsoft.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Jessica Yu <jeyu@kernel.org>,
	x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
	linux-mm@kvack.org
Subject: [PATCH 1/3] x86/hyperv: allocate the hypercall page with only read and execute bits
Date: Thu, 18 Jun 2020 08:43:05 +0200	[thread overview]
Message-ID: <20200618064307.32739-2-hch@lst.de> (raw)
In-Reply-To: <20200618064307.32739-1-hch@lst.de>

Avoid a W^X violation cause by the fact that PAGE_KERNEL_EXEC includes the
writable bit.

For this resurrect the removed PAGE_KERNEL_RX definitіon, but as
PAGE_KERNEL_ROX to match arm64 and powerpc.

Fixes: 78bb17f76edc ("x86/hyperv: use vmalloc_exec for the hypercall page")
Reported-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 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..2bdc72e6890eca 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_ROX,
+			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..816b31c685505f 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_ROX	 (__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_ROX		__pgprot_mask(__PAGE_KERNEL_ROX        | _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


  reply	other threads:[~2020-06-18  6:43 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-18  6:43 fix a hyperv W^X violation and remove vmalloc_exec Christoph Hellwig
2020-06-18  6:43 ` Christoph Hellwig [this message]
2020-06-18 11:47   ` [PATCH 1/3] x86/hyperv: allocate the hypercall page with only read and execute bits Wei Liu
2020-06-18  6:43 ` [PATCH 2/3] arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page Christoph Hellwig
2020-06-18  8:55   ` David Hildenbrand
2020-06-18 10:35     ` Peter Zijlstra
2020-06-18 13:50       ` Christoph Hellwig
2020-06-18  9:27   ` Peter Zijlstra
2020-06-21  2:16   ` Andrew Morton
2020-06-23  9:05     ` Christoph Hellwig
2020-06-23  9:07       ` Will Deacon
2020-06-23  9:37         ` Peter Zijlstra
2020-06-23  9:57           ` Will Deacon
2020-06-27  7:34   ` Ard Biesheuvel
2020-06-27  7:56     ` Christoph Hellwig
2020-06-27  7:57       ` Ard Biesheuvel
2020-06-18  6:43 ` [PATCH 3/3] mm: remove vmalloc_exec Christoph Hellwig
2020-06-18  8:53   ` David Hildenbrand
2020-06-18  9:28 ` fix a hyperv W^X violation and " Peter Zijlstra

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