Hi Sean, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on kvm/linux-next] [also build test WARNING on v4.19-rc1 next-20180830] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Sean-Christopherson/KVM-nVMX-add-option-to-perform-early-consistency-checks-via-H-W/20180830-231534 base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next config: i386-randconfig-x076-201834 (attached as .config) compiler: gcc-7 (Debian 7.3.0-16) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=i386 All warnings (new ones prefixed by >>): arch/x86/kvm/vmx.c: In function 'nested_vmx_check_vmentry_hw': >> arch/x86/kvm/vmx.c:12595:25: warning: large integer implicitly truncated to unsigned type [-Woverflow] vmcs_writel(GUEST_RIP, 0xf0f0ULL << 48); ^~~~~~~~~ vim +12595 arch/x86/kvm/vmx.c 12573 12574 static int __noclone nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu) 12575 { 12576 struct vcpu_vmx *vmx = to_vmx(vcpu); 12577 unsigned long cr3, cr4; 12578 12579 if (!early_consistency_checks) 12580 return 0; 12581 12582 if (vmx->msr_autoload.host.nr) 12583 vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, 0); 12584 if (vmx->msr_autoload.guest.nr) 12585 vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, 0); 12586 12587 preempt_disable(); 12588 12589 vmx_prepare_switch_to_guest(vcpu); 12590 12591 /* 12592 * prepare_vmcs02() writes GUEST_RIP unconditionally, no need 12593 * to save/restore or set dirty bits. 12594 */ 12595 vmcs_writel(GUEST_RIP, 0xf0f0ULL << 48); 12596 12597 vmcs_writel(HOST_RIP, vmx_early_consistency_check_return); 12598 12599 cr3 = __get_current_cr3_fast(); 12600 if (unlikely(cr3 != vmx->loaded_vmcs->host_state.cr3)) { 12601 vmcs_writel(HOST_CR3, cr3); 12602 vmx->loaded_vmcs->host_state.cr3 = cr3; 12603 } 12604 12605 cr4 = cr4_read_shadow(); 12606 if (unlikely(cr4 != vmx->loaded_vmcs->host_state.cr4)) { 12607 vmcs_writel(HOST_CR4, cr4); 12608 vmx->loaded_vmcs->host_state.cr4 = cr4; 12609 } 12610 12611 vmx->__launched = vmx->loaded_vmcs->launched; 12612 12613 asm( 12614 /* Set HOST_RSP */ 12615 __ex(ASM_VMX_VMWRITE_RSP_RDX) "\n\t" 12616 "mov %%" _ASM_SP ", %c[host_rsp](%0)\n\t" 12617 12618 /* Check if vmlaunch of vmresume is needed */ 12619 "cmpl $0, %c[launched](%0)\n\t" 12620 "je 1f\n\t" 12621 __ex(ASM_VMX_VMRESUME) "\n\t" 12622 "jmp 2f\n\t" 12623 "1: " __ex(ASM_VMX_VMLAUNCH) "\n\t" 12624 "jmp 2f\n\t" 12625 "2: " 12626 12627 /* Set vmx->fail accordingly */ 12628 "setbe %c[fail](%0)\n\t" 12629 12630 ".pushsection .rodata\n\t" 12631 ".global vmx_early_consistency_check_return\n\t" 12632 "vmx_early_consistency_check_return: " _ASM_PTR " 2b\n\t" 12633 ".popsection" 12634 : 12635 : "c"(vmx), "d"((unsigned long)HOST_RSP), 12636 [launched]"i"(offsetof(struct vcpu_vmx, __launched)), 12637 [fail]"i"(offsetof(struct vcpu_vmx, fail)), 12638 [host_rsp]"i"(offsetof(struct vcpu_vmx, host_rsp)) 12639 : "rax", "cc", "memory" 12640 ); 12641 12642 vmcs_writel(HOST_RIP, vmx_return); 12643 12644 preempt_enable(); 12645 12646 if (vmx->msr_autoload.host.nr) 12647 vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr); 12648 if (vmx->msr_autoload.guest.nr) 12649 vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr); 12650 12651 if (vmx->fail) { 12652 WARN_ON_ONCE(vmcs_read32(VM_INSTRUCTION_ERROR) != 12653 VMXERR_ENTRY_INVALID_CONTROL_FIELD); 12654 vmx->fail = 0; 12655 return 1; 12656 } 12657 12658 /* 12659 * VMExit clears RFLAGS.IF and DR7, even on a consistency check. 12660 */ 12661 local_irq_enable(); 12662 if (hw_breakpoint_active()) 12663 set_debugreg(__this_cpu_read(cpu_dr7), 7); 12664 12665 /* 12666 * A non-failing VMEntry means we somehow entered guest mode with 12667 * an illegal RIP, and that's just the tip of the iceberg. There 12668 * is no telling what memory has been modified or what state has 12669 * been exposed to unknown code. Hitting this all but guarantees 12670 * a (very critical) hardware issue. 12671 */ 12672 WARN_ON(!(vmcs_read32(VM_EXIT_REASON) & 12673 VMX_EXIT_REASONS_FAILED_VMENTRY)); 12674 12675 return 0; 12676 } 12677 STACK_FRAME_NON_STANDARD(nested_vmx_check_vmentry_hw); 12678 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
Attachment:
.config.gz
Description: application/gzip
