Re: [Qemu-devel] [PATCH 1/3] xics/spapr: Prevent RTAS/hypercalls emulation to be used by in-kernel XICS

[Greg Kurz <groug@kaod.org>]

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On Fri, 14 Jun 2019 11:34:59 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Thu, Jun 13, 2019 at 06:44:54PM +0200, Greg Kurz wrote:
> > The XICS-related RTAS calls and hypercalls in QEMU are supposed to be
> > called only when the KVM in-kernel XICS is in use.  
> 
> I've applied this, but reversed the sense of the sentence above, which
> appears to be the intent.
> 

Oops indeed... Thanks !

> > 
> > Add some explicit checks to detect that, print an error message and report
> > an hardware error to the guest.
> > 
> > Signed-off-by: Greg Kurz <groug@kaod.org>
> > ---
> >  hw/intc/xics_spapr.c |   46 ++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 46 insertions(+)
> > 
> > diff --git a/hw/intc/xics_spapr.c b/hw/intc/xics_spapr.c
> > index 5a1835e8b1ed..d470ab5f7a2a 100644
> > --- a/hw/intc/xics_spapr.c
> > +++ b/hw/intc/xics_spapr.c
> > @@ -41,11 +41,31 @@
> >   * Guest interfaces
> >   */
> >  
> > +static bool check_in_kernel_xics(const char *func)
> > +{
> > +    if (kvm_irqchip_in_kernel()) {
> > +        error_report("pseries: %s must never be called for in-kernel XICS",
> > +                     func);
> > +        return true;
> > +    }
> > +
> > +    return false;
> > +}
> > +
> > +#define CHECK_IN_KERNEL_XICS_HCALL              \
> > +    do {                                        \
> > +        if (check_in_kernel_xics(__func__)) {   \
> > +            return H_HARDWARE;                  \
> > +        }                                       \
> > +    } while (0)
> > +
> >  static target_ulong h_cppr(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >                             target_ulong opcode, target_ulong *args)
> >  {
> >      target_ulong cppr = args[0];
> >  
> > +    CHECK_IN_KERNEL_XICS_HCALL;
> > +
> >      icp_set_cppr(spapr_cpu_state(cpu)->icp, cppr);
> >      return H_SUCCESS;
> >  }
> > @@ -56,6 +76,8 @@ static target_ulong h_ipi(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >      target_ulong mfrr = args[1];
> >      ICPState *icp = xics_icp_get(XICS_FABRIC(spapr), args[0]);
> >  
> > +    CHECK_IN_KERNEL_XICS_HCALL;
> > +
> >      if (!icp) {
> >          return H_PARAMETER;
> >      }
> > @@ -69,6 +91,8 @@ static target_ulong h_xirr(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >  {
> >      uint32_t xirr = icp_accept(spapr_cpu_state(cpu)->icp);
> >  
> > +    CHECK_IN_KERNEL_XICS_HCALL;
> > +
> >      args[0] = xirr;
> >      return H_SUCCESS;
> >  }
> > @@ -78,6 +102,8 @@ static target_ulong h_xirr_x(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >  {
> >      uint32_t xirr = icp_accept(spapr_cpu_state(cpu)->icp);
> >  
> > +    CHECK_IN_KERNEL_XICS_HCALL;
> > +
> >      args[0] = xirr;
> >      args[1] = cpu_get_host_ticks();
> >      return H_SUCCESS;
> > @@ -88,6 +114,8 @@ static target_ulong h_eoi(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >  {
> >      target_ulong xirr = args[0];
> >  
> > +    CHECK_IN_KERNEL_XICS_HCALL;
> > +
> >      icp_eoi(spapr_cpu_state(cpu)->icp, xirr);
> >      return H_SUCCESS;
> >  }
> > @@ -99,6 +127,8 @@ static target_ulong h_ipoll(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >      uint32_t mfrr;
> >      uint32_t xirr;
> >  
> > +    CHECK_IN_KERNEL_XICS_HCALL;
> > +
> >      if (!icp) {
> >          return H_PARAMETER;
> >      }
> > @@ -111,6 +141,14 @@ static target_ulong h_ipoll(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >      return H_SUCCESS;
> >  }
> >  
> > +#define CHECK_IN_KERNEL_XICS_RTAS(rets)                 \
> > +    do {                                                \
> > +        if (check_in_kernel_xics(__func__)) {           \
> > +            rtas_st((rets), 0, RTAS_OUT_HW_ERROR);      \
> > +            return;                                     \
> > +        }                                               \
> > +    } while (0)
> > +
> >  static void rtas_set_xive(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >                            uint32_t token,
> >                            uint32_t nargs, target_ulong args,
> > @@ -119,6 +157,8 @@ static void rtas_set_xive(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >      ICSState *ics = spapr->ics;
> >      uint32_t nr, srcno, server, priority;
> >  
> > +    CHECK_IN_KERNEL_XICS_RTAS(rets);
> > +
> >      if ((nargs != 3) || (nret != 1)) {
> >          rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> >          return;
> > @@ -152,6 +192,8 @@ static void rtas_get_xive(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >      ICSState *ics = spapr->ics;
> >      uint32_t nr, srcno;
> >  
> > +    CHECK_IN_KERNEL_XICS_RTAS(rets);
> > +
> >      if ((nargs != 1) || (nret != 3)) {
> >          rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> >          return;
> > @@ -182,6 +224,8 @@ static void rtas_int_off(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >      ICSState *ics = spapr->ics;
> >      uint32_t nr, srcno;
> >  
> > +    CHECK_IN_KERNEL_XICS_RTAS(rets);
> > +
> >      if ((nargs != 1) || (nret != 1)) {
> >          rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> >          return;
> > @@ -213,6 +257,8 @@ static void rtas_int_on(PowerPCCPU *cpu, SpaprMachineState *spapr,
> >      ICSState *ics = spapr->ics;
> >      uint32_t nr, srcno;
> >  
> > +    CHECK_IN_KERNEL_XICS_RTAS(rets);
> > +
> >      if ((nargs != 1) || (nret != 1)) {
> >          rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> >          return;
> >   
> 


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