From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Garnier via Virtualization Subject: [RFC v3 18/27] kvm: Adapt assembly for PIE support Date: Wed, 4 Oct 2017 14:19:54 -0700 Message-ID: <20171004212003.28296-19-thgarnie__48950.8301638581$1509079919$gmane$org@google.com> References: <20171004212003.28296-1-thgarnie@google.com> Reply-To: Thomas Garnier Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20171004212003.28296-1-thgarnie@google.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Herbert Xu , "David S . Miller" , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , Josh Poimboeuf , Thomas Garnier , Arnd Bergmann , Kees Cook , Matthias Kaehlcke , Tom Lendacky , Andy Lutomirski , "Kirill A . Shutemov" , Borislav Petkov , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Juergen Gross , Chris Wright , Alok Kataria , Rusty Russell , Tejun Heo , Christoph Lameter Bor Cc: linux-arch@vger.kernel.org, kvm@vger.kernel.org, linux-pm@vger.kernel.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-sparse@vger.kernel.org, linux-crypto@vger.kernel.org, kernel-hardening@lists.openwall.com, xen-devel@lists.xenproject.org List-Id: virtualization@lists.linuxfoundation.org Change the assembly code to use only relative references of symbols for the kernel to be PIE compatible. The new __ASM_GET_PTR_PRE 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 extended the KASLR randomization range below the -2G memory limit. Signed-off-by: Thomas Garnier --- arch/x86/include/asm/kvm_host.h | 6 ++++-- arch/x86/kernel/kvm.c | 6 ++++-- arch/x86/kvm/svm.c | 4 ++-- 3 files changed, 10 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 9d7d856b2d89..14073fda75fb 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1342,9 +1342,11 @@ 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) "%%" _ASM_AX " \n\t" \ + __ASM_GET_PTR_PRE(666b) "%%" _ASM_AX "\n\t" \ + "xchg %%" _ASM_AX ", (%%" _ASM_SP ") \n\t" \ "call 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 aa60a08b65b1..07176bfc188b 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -620,8 +620,10 @@ 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 0e68f0b3cbf7..364536080438 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -568,12 +568,12 @@ static u32 svm_msrpm_offset(u32 msr) static inline void clgi(void) { - asm volatile (__ex(SVM_CLGI)); + asm volatile (__ex(SVM_CLGI) : :); } static inline void stgi(void) { - asm volatile (__ex(SVM_STGI)); + asm volatile (__ex(SVM_STGI) : :); } static inline void invlpga(unsigned long addr, u32 asid) -- 2.14.2.920.gcf0c67979c-goog