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From: Alexander Graf <agraf@suse.de>
To: kvm-ppc@vger.kernel.org
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	mtosatti@redhat.com
Subject: [PULL 4/4] KVM guest: Make pv trampoline code executable
Date: Mon, 12 May 2014 22:26:06 +0200	[thread overview]
Message-ID: <1399926366-19538-5-git-send-email-agraf@suse.de> (raw)
In-Reply-To: <1399926366-19538-1-git-send-email-agraf@suse.de>

Our PV guest patching code assembles chunks of instructions on the fly when it
encounters more complicated instructions to hijack. These instructions need
to live in a section that we don't mark as non-executable, as otherwise we
fault when jumping there.

Right now we put it into the .bss section where it automatically gets marked
as non-executable. Add a check to the NX setting function to ensure that we
leave these particular pages executable.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 arch/powerpc/include/asm/sections.h | 11 +++++++++++
 arch/powerpc/kernel/kvm.c           |  2 +-
 arch/powerpc/mm/hash_utils_64.c     |  4 ++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index d0e784e..5217903 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -39,6 +39,17 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
 		(unsigned long)_stext < end;
 }
 
+static inline int overlaps_kvm_tmp(unsigned long start, unsigned long end)
+{
+#ifdef CONFIG_KVM_GUEST
+	extern char kvm_tmp[];
+	return start < (unsigned long)kvm_tmp &&
+		(unsigned long)&kvm_tmp[1024 * 1024] < end;
+#else
+	return 0;
+#endif
+}
+
 #undef dereference_function_descriptor
 static inline void *dereference_function_descriptor(void *ptr)
 {
diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index 6a01752..dd8695f 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -74,7 +74,7 @@
 #define KVM_INST_MTSRIN		0x7c0001e4
 
 static bool kvm_patching_worked = true;
-static char kvm_tmp[1024 * 1024];
+char kvm_tmp[1024 * 1024];
 static int kvm_tmp_index;
 
 static inline void kvm_patch_ins(u32 *inst, u32 new_inst)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index d766d6e..06ba83b 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -207,6 +207,10 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 		if (overlaps_kernel_text(vaddr, vaddr + step))
 			tprot &= ~HPTE_R_N;
 
+		/* Make kvm guest trampolines executable */
+		if (overlaps_kvm_tmp(vaddr, vaddr + step))
+			tprot &= ~HPTE_R_N;
+
 		/*
 		 * If relocatable, check if it overlaps interrupt vectors that
 		 * are copied down to real 0. For relocatable kernel
-- 
1.8.1.4


WARNING: multiple messages have this Message-ID (diff)
From: Alexander Graf <agraf@suse.de>
To: kvm-ppc@vger.kernel.org
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	mtosatti@redhat.com
Subject: [PULL 4/4] KVM guest: Make pv trampoline code executable
Date: Mon, 12 May 2014 20:26:06 +0000	[thread overview]
Message-ID: <1399926366-19538-5-git-send-email-agraf@suse.de> (raw)
In-Reply-To: <1399926366-19538-1-git-send-email-agraf@suse.de>

Our PV guest patching code assembles chunks of instructions on the fly when it
encounters more complicated instructions to hijack. These instructions need
to live in a section that we don't mark as non-executable, as otherwise we
fault when jumping there.

Right now we put it into the .bss section where it automatically gets marked
as non-executable. Add a check to the NX setting function to ensure that we
leave these particular pages executable.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 arch/powerpc/include/asm/sections.h | 11 +++++++++++
 arch/powerpc/kernel/kvm.c           |  2 +-
 arch/powerpc/mm/hash_utils_64.c     |  4 ++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index d0e784e..5217903 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -39,6 +39,17 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
 		(unsigned long)_stext < end;
 }
 
+static inline int overlaps_kvm_tmp(unsigned long start, unsigned long end)
+{
+#ifdef CONFIG_KVM_GUEST
+	extern char kvm_tmp[];
+	return start < (unsigned long)kvm_tmp &&
+		(unsigned long)&kvm_tmp[1024 * 1024] < end;
+#else
+	return 0;
+#endif
+}
+
 #undef dereference_function_descriptor
 static inline void *dereference_function_descriptor(void *ptr)
 {
diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index 6a01752..dd8695f 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -74,7 +74,7 @@
 #define KVM_INST_MTSRIN		0x7c0001e4
 
 static bool kvm_patching_worked = true;
-static char kvm_tmp[1024 * 1024];
+char kvm_tmp[1024 * 1024];
 static int kvm_tmp_index;
 
 static inline void kvm_patch_ins(u32 *inst, u32 new_inst)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index d766d6e..06ba83b 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -207,6 +207,10 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 		if (overlaps_kernel_text(vaddr, vaddr + step))
 			tprot &= ~HPTE_R_N;
 
+		/* Make kvm guest trampolines executable */
+		if (overlaps_kvm_tmp(vaddr, vaddr + step))
+			tprot &= ~HPTE_R_N;
+
 		/*
 		 * If relocatable, check if it overlaps interrupt vectors that
 		 * are copied down to real 0. For relocatable kernel
-- 
1.8.1.4


  parent reply	other threads:[~2014-05-12 20:26 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-12 20:26 [PULL 3.15 0/4] 3.15 patch queue 2014-05-12 Alexander Graf
2014-05-12 20:26 ` Alexander Graf
2014-05-12 20:26 ` [PULL 1/4] KVM: PPC: Book3S: HV: make _PAGE_NUMA take effect Alexander Graf
2014-05-12 20:26   ` Alexander Graf
2014-05-12 20:26 ` [PULL 2/4] KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit Alexander Graf
2014-05-12 20:26   ` Alexander Graf
2014-05-12 20:26 ` [PULL 3/4] KVM: PPC: Book3S: ifdef on CONFIG_KVM_BOOK3S_32_HANDLER for 32bit Alexander Graf
2014-05-12 20:26   ` Alexander Graf
2014-05-12 20:26 ` Alexander Graf [this message]
2014-05-12 20:26   ` [PULL 4/4] KVM guest: Make pv trampoline code executable Alexander Graf
2014-05-13 16:15 ` [PULL 3.15 0/4] 3.15 patch queue 2014-05-12 Paolo Bonzini
2014-05-13 16:15   ` Paolo Bonzini

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