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Message-Id: <20190131192533.34130-20-thgarnie@chromium.org>
Date: Thu, 31 Jan 2019 11:24:26 -0800
From: Thomas Garnier <thgarnie@...omium.org>
To: kernel-hardening@...ts.openwall.com
Cc: kristen@...ux.intel.com,
Thomas Garnier <thgarnie@...omium.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Radim Krčmář <rkrcmar@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>,
x86@...nel.org,
Joerg Roedel <joro@...tes.org>,
kvm@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v6 19/27] kvm: Adapt assembly for PIE support
Change the assembly code to use only relative references of symbols for the
kernel to be PIE compatible. The new __ASM_MOVABS macro is used to
get the address of a symbol on both 32 and 64-bit with PIE support.
Position Independent Executable (PIE) support will allow to extend the
KASLR randomization range below 0xffffffff80000000.
Signed-off-by: Thomas Garnier <thgarnie@...omium.org>
---
arch/x86/include/asm/kvm_host.h | 8 ++++++--
arch/x86/kernel/kvm.c | 6 ++++--
arch/x86/kvm/svm.c | 4 ++--
arch/x86/kvm/vmx/vmx.c | 2 +-
4 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4660ce90de7f..fdb3307d5fe1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1498,9 +1498,13 @@ asmlinkage void kvm_spurious_fault(void);
".pushsection .fixup, \"ax\" \n" \
"667: \n\t" \
cleanup_insn "\n\t" \
- "cmpb $0, kvm_rebooting \n\t" \
+ "cmpb $0, kvm_rebooting" __ASM_SEL(, (%%rip)) " \n\t" \
"jne 668b \n\t" \
- __ASM_SIZE(push) " $666b \n\t" \
+ __ASM_SIZE(push) "$0 \n\t" \
+ __ASM_SIZE(push) "%%" _ASM_AX " \n\t" \
+ _ASM_MOVABS " $666b, %%" _ASM_AX "\n\t" \
+ _ASM_MOV " %%" _ASM_AX ", " __ASM_SEL(4, 8) "(%%" _ASM_SP ") \n\t" \
+ __ASM_SIZE(pop) "%%" _ASM_AX " \n\t" \
"jmp kvm_spurious_fault \n\t" \
".popsection \n\t" \
_ASM_EXTABLE(666b, 667b)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5c93a65ee1e5..f6eb02004e43 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -826,8 +826,10 @@ asm(
".global __raw_callee_save___kvm_vcpu_is_preempted;"
".type __raw_callee_save___kvm_vcpu_is_preempted, @function;"
"__raw_callee_save___kvm_vcpu_is_preempted:"
-"movq __per_cpu_offset(,%rdi,8), %rax;"
-"cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);"
+"leaq __per_cpu_offset(%rip), %rax;"
+"movq (%rax,%rdi,8), %rax;"
+"addq " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rip), %rax;"
+"cmpb $0, (%rax);"
"setne %al;"
"ret;"
".popsection");
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f13a3a24d360..26abb82b1b67 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -706,12 +706,12 @@ static u32 svm_msrpm_offset(u32 msr)
static inline void clgi(void)
{
- asm volatile (__ex("clgi"));
+ asm volatile (__ex("clgi") : :);
}
static inline void stgi(void)
{
- asm volatile (__ex("stgi"));
+ asm volatile (__ex("stgi") : :);
}
static inline void invlpga(unsigned long addr, u32 asid)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4341175339f3..3275761a7375 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2161,7 +2161,7 @@ static void vmclear_local_loaded_vmcss(void)
*/
static void kvm_cpu_vmxoff(void)
{
- asm volatile (__ex("vmxoff"));
+ asm volatile (__ex("vmxoff") :::);
intel_pt_handle_vmx(0);
cr4_clear_bits(X86_CR4_VMXE);
--
2.20.1.495.gaa96b0ce6b-goog
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