From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Garnier Subject: [PATCH v6 19/27] kvm: Adapt assembly for PIE support Date: Thu, 31 Jan 2019 11:24:26 -0800 Message-Id: <20190131192533.34130-20-thgarnie@chromium.org> In-Reply-To: <20190131192533.34130-1-thgarnie@chromium.org> References: <20190131192533.34130-1-thgarnie@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: kernel-hardening@lists.openwall.com Cc: kristen@linux.intel.com, Thomas Garnier , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: 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 --- 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