Re: [RFC PATCH v1 1/4] kvmppc: HMM backend driver to manage pages of secure guest

[Paul Mackerras <paulus@ozlabs.org>]

On Mon, Oct 29, 2018 at 11:31:55PM -0700, Ram Pai wrote:
> On Tue, Oct 30, 2018 at 04:03:00PM +1100, Paul Mackerras wrote:
> > On Mon, Oct 22, 2018 at 10:48:34AM +0530, Bharata B Rao wrote:
> > > HMM driver for KVM PPC to manage page transitions of
> > > secure guest via H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls.
> > > 
> > > H_SVM_PAGE_IN: Move the content of a normal page to secure page
> > > H_SVM_PAGE_OUT: Move the content of a secure page to normal page
> > 
> > Comments below...
> > 
> > > Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
> > > ---
> > >  /* pSeries hypervisor opcodes */
> ....
> > >  #define H_REMOVE		0x04
> > >  #define H_ENTER			0x08
> > > @@ -295,7 +298,9 @@
> > >  #define H_INT_ESB               0x3C8
> > >  #define H_INT_SYNC              0x3CC
> > >  #define H_INT_RESET             0x3D0
> > > -#define MAX_HCALL_OPCODE	H_INT_RESET
> > > +#define H_SVM_PAGE_IN		0x3D4
> > > +#define H_SVM_PAGE_OUT		0x3D8
> > > +#define MAX_HCALL_OPCODE	H_SVM_PAGE_OUT
> > 
> > We should define hcall numbers in the implementation-specific range.
> > We can't use numbers in this range without first getting them
> > standardized in PAPR.  Since these hcalls are not actually used by
> > the guest but are just a private interface between KVM and the
> > ultravisor, it's probably not worth putting them in PAPR.  We should
> > pick a range somewhere in the 0xf000 - 0xfffc area and use that.
> 
> We are using that range for Ucalls.  For hcalls we were told to reserve
> a range between 1024(0x400) to  2047(0x7FF). Have to reserve them in the
> appropriate database.

Who gave you that advice?

Paul.