[PATCH v2 19/27] kvm: Adapt assembly for PIE support
From: Thomas Garnier <hidden>
Date: 2018-03-13 20:59:37
Also in:
kvm, linux-arch, linux-pm, lkml, xen-devel
Subsystem:
kernel virtual machine for x86 (kvm/x86), kvm paravirt (kvm/paravirt), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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 extended the KASLR randomization range below the -2G memory limit. Signed-off-by: Thomas Garnier <redacted> --- 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 b605a5b6a30c..7bd6ba79e778 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h@@ -1380,9 +1380,11 @@ 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_MOVABS " $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 bc1a27280c4b..5e4dd958ea95 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c@@ -711,8 +711,10 @@ 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 be9c839e2c89..6835a2ce02e5 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c@@ -626,12 +626,12 @@ 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)
--
2.16.2.660.g709887971b-goog
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel