On 1/15/19 11:43 AM, Qian Cai wrote: > > > On 1/15/19 2:13 AM, Paolo Bonzini wrote: >> Hmm, maybe like this: >> >> diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S >> index bcef2c7e9bc4..33122fa9d4bd 100644 >> --- a/arch/x86/kvm/vmx/vmenter.S >> +++ b/arch/x86/kvm/vmx/vmenter.S >> @@ -26,19 +26,17 @@ ENTRY(vmx_vmenter) >> ret >> >> 2: vmlaunch >> +3: >> ret >> >> -3: cmpb $0, kvm_rebooting >> - jne 4f >> - call kvm_spurious_fault >> -4: ret >> - >> .pushsection .fixup, "ax" >> -5: jmp 3b >> +4: cmpb $0, kvm_rebooting >> + jne 3b >> + jmp kvm_spurious_fault >> .popsection >> >> - _ASM_EXTABLE(1b, 5b) >> - _ASM_EXTABLE(2b, 5b) >> + _ASM_EXTABLE(1b, 4b) >> + _ASM_EXTABLE(2b, 4b) >> >> ENDPROC(vmx_vmenter) > > No, that will not work. The problem is in vmx.o where I just sent another patch > for it. > > I can see there are five options to solve it. > > 1) always inline vmx_vcpu_run() > 2) always noinline vmx_vcpu_run() > 3) add -fdiable-ipa-fnsplit option to Makefile for vmx.o > 4) let STACK_FRAME_NON_STANDARD support part.* syntax. > 5) trim-down vmx_vcpu_run() even more to not causing splitting by GCC. > > Option 1) and 2) seems give away the decision for user with > CONFIG_CC_OPTIMIZE_FOR_(PERFORMANCE/SIZE). > > Option 3) prevents other functions there for splitting for optimization. > > Option 4) and 5) seems tricky to implement. > > I am not more leaning to 3) as only other fuction will miss splitting is > vmx_segment_access_rights(). > Option 3) seems a bit tricky to implement too, as it needs to check for the compiler version before to see if the option is available before put it to the CFLAGS.
