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

[David Gibson]

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.

> 
> Add some explicit checks to detect that, print an error message and report
> an hardware error to the guest.
> 
> Signed-off-by: Greg Kurz <address@hidden>
> ---
>  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;
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

signature.asc
Description: PGP signature