Re: [Qemu-devel] [PULL 07/28] x86/cpu: use standard-headers/asm-x86.kvm_para.h

[Peter Maydell]

On 23 May 2018 at 15:43, Michael S. Tsirkin <address@hidden> wrote:
> Switch to the header we imported from Linux,
> this allows us to drop a hack in kvm_i386.h.
> More code will be dropped in the next patch.
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>

> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -688,8 +688,6 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
>  #define CPUID_7_0_EDX_SPEC_CTRL     (1U << 26) /* Speculation Control */
>  #define CPUID_7_0_EDX_SPEC_CTRL_SSBD  (1U << 31) /* Speculative Store Bypass 
> Disable */
>
> -#define KVM_HINTS_DEDICATED (1U << 0)
> -
>  #define CPUID_8000_0008_EBX_IBPB    (1U << 12) /* Indirect Branch Prediction 
> Barrier */
>
>  #define CPUID_XSAVE_XSAVEOPT   (1U << 0)

Hi -- this seems like it will break compilation when we next
update our copy of the Linux kernel headers, because (as of
4.17-rc6, at least), asm-x86/kvm_para.h doesn't define
KVM_HINTS_DEDICATED. Here's the diff I get as part of
my attempt to run update-linux-headers:

--- a/include/standard-headers/asm-x86/kvm_para.h
+++ b/include/standard-headers/asm-x86/kvm_para.h
@@ -29,7 +29,7 @@
 #define KVM_FEATURE_PV_TLB_FLUSH       9
 #define KVM_FEATURE_ASYNC_PF_VMEXIT    10

-#define KVM_HINTS_DEDICATED      0
+#define KVM_HINTS_REALTIME      0

 /* The last 8 bits are used to indicate how to interpret the flags field
  * in pvclock structure. If no bits are set, all flags are ignored.

I'm not sure what's going on here -- commit 633711e8287 in
the kernel just renames the constant, but doesn't that
break userspace API ?

thanks
-- PMM