Re: [PATCH v3 40/75] x86/sev-es: Compile early handler code into kernel image

Joerg Roedel
2020-06-04T11:54:13Z

On Wed, May 20, 2020 at 11:14:15AM +0200, Borislav Petkov wrote:
> On Tue, Apr 28, 2020 at 05:16:50PM +0200, Joerg Roedel wrote:
> > +static inline u64 sev_es_rd_ghcb_msr(void)
> > +{
> > + return native_read_msr(MSR_AMD64_SEV_ES_GHCB);
> > +}
> > +
> > +static inline void sev_es_wr_ghcb_msr(u64 val)
> > +{
> > + u32 low, high;
> > +
> > + low = (u32)(val);
> > + high = (u32)(val >> 32);
> > +
> > + native_write_msr(MSR_AMD64_SEV_ES_GHCB, low, high);
> > +}
>
> Instead of duplicating those two, you can lift the ones in the
> compressed image into sev-es.h and use them here. I don't care one bit
> about the MSR tracepoints in native_*_msr().

It is not only the trace-point, this would also eliminate exception
handling in case the MSR access triggers a #GP. The "Unhandled MSR
read/write" messages would turn into a "General Protection Fault"
message.

Joerg