On Fri, May 25, 2018 at 12:53:44PM +0100, Peter Maydell wrote:
> On 25 May 2018 at 12:06, Peter Maydell <peter.maydell@xxxxxxxxxx> wrote:
> > On 23 May 2018 at 15:43, Michael S. Tsirkin <mst@xxxxxxxxxx> 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 <mst@xxxxxxxxxx>
> >
> >> --- 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.
>
> For the moment I'm using this workaround (I wanted to do a header
> update for something else I'm working on):
>
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -48,6 +48,11 @@
> #include "exec/memattrs.h"
> #include "trace.h"
>
> +/* Work around this kernel header constant changing its name */
> +#ifndef KVM_HINTS_REALTIME
> +#define KVM_HINTS_REALTIME KVM_HINTS_DEDICATED
> +#endif
> +
> //#define DEBUG_KVM
>
> #ifdef DEBUG_KVM
I don't think we need this chunk.
> @@ -387,7 +392,7 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s,
> uint32_t function,
> ret &= ~(1U << KVM_FEATURE_PV_UNHALT);
> }
> } else if (function == KVM_CPUID_FEATURES && reg == R_EDX) {
> - ret |= 1U << KVM_HINTS_DEDICATED;
> + ret |= 1U << KVM_HINTS_REALTIME;
> found = 1;
> }
That's the right change when we update this header.
> thanks
> -- PMM
