Messages in this thread Patch in this message | | | Subject | [PATCH 3/4] KVM: Clean up AMD SVM debug registers load and unload | From | Avi Kivity <> | Date | Sun, 10 Dec 2006 17:11:42 -0000 |
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By letting gcc choose the temporary register for us, we lose arch dependency and some ugliness. Conceivably gcc will also generate marginally better code.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Index: linux-2.6/drivers/kvm/svm.c =================================================================== --- linux-2.6.orig/drivers/kvm/svm.c +++ linux-2.6/drivers/kvm/svm.c @@ -1345,53 +1345,18 @@ static void kvm_reput_irq(struct kvm_vcp static void save_db_regs(unsigned long *db_regs) { -#ifdef __x86_64__ - asm ("mov %%dr0, %%rax \n\t" - "mov %%rax, %[dr0] \n\t" - "mov %%dr1, %%rax \n\t" - "mov %%rax, %[dr1] \n\t" - "mov %%dr2, %%rax \n\t" - "mov %%rax, %[dr2] \n\t" - "mov %%dr3, %%rax \n\t" - "mov %%rax, %[dr3] \n\t" - : [dr0] "=m"(db_regs[0]), - [dr1] "=m"(db_regs[1]), - [dr2] "=m"(db_regs[2]), - [dr3] "=m"(db_regs[3]) - : : "rax"); -#else - asm ("mov %%dr0, %%eax \n\t" - "mov %%eax, %[dr0] \n\t" - "mov %%dr1, %%eax \n\t" - "mov %%eax, %[dr1] \n\t" - "mov %%dr2, %%eax \n\t" - "mov %%eax, %[dr2] \n\t" - "mov %%dr3, %%eax \n\t" - "mov %%eax, %[dr3] \n\t" - : [dr0] "=m"(db_regs[0]), - [dr1] "=m"(db_regs[1]), - [dr2] "=m"(db_regs[2]), - [dr3] "=m"(db_regs[3]) - : : "eax"); -#endif + asm volatile ("mov %%dr0, %0" : "=r"(db_regs[0])); + asm volatile ("mov %%dr1, %0" : "=r"(db_regs[1])); + asm volatile ("mov %%dr2, %0" : "=r"(db_regs[2])); + asm volatile ("mov %%dr3, %0" : "=r"(db_regs[3])); } static void load_db_regs(unsigned long *db_regs) { - asm volatile ("mov %[dr0], %%dr0 \n\t" - "mov %[dr1], %%dr1 \n\t" - "mov %[dr2], %%dr2 \n\t" - "mov %[dr3], %%dr3 \n\t" - : - : [dr0] "r"(db_regs[0]), - [dr1] "r"(db_regs[1]), - [dr2] "r"(db_regs[2]), - [dr3] "r"(db_regs[3]) -#ifdef __x86_64__ - : "rax"); -#else - : "eax"); -#endif + asm volatile ("mov %0, %%dr0" : : "r"(db_regs[0])); + asm volatile ("mov %0, %%dr1" : : "r"(db_regs[1])); + asm volatile ("mov %0, %%dr2" : : "r"(db_regs[2])); + asm volatile ("mov %0, %%dr3" : : "r"(db_regs[3])); } static int svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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