Messages in this thread | | | From | Jim Mattson <> | Date | Wed, 14 Feb 2018 16:46:46 -0800 | Subject | Re: [PATCH v2 1/4] x86/speculation: Use IBRS if available before calling into firmware |
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On Wed, Feb 14, 2018 at 3:29 PM, David Woodhouse <dwmw@amazon.co.uk> wrote:
> +#define alternative_msr_write(_msr, _val, _feature) \ > + asm volatile(ALTERNATIVE("", \ > + "movl %[msr], %%ecx\n\t" \ > + "movl %[val], %%eax\n\t" \ > + "movl $0, %%edx\n\t" \ > + "wrmsr", \ > + _feature) \ > + : : [msr] "i" (_msr), [val] "i" (_val) \ > + : "eax", "ecx", "edx", "memory") > +
It's not needed now, but this would be more generally useful if the high 32 bits of the MSR value could also be specified.
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