Re: [PATCH v9 11/15] s390x: protvirt: Disable address checks for PV guest IO emulation

[Cornelia Huck]

On Wed, 11 Mar 2020 09:21:47 -0400
Janosch Frank <address@hidden> wrote:

> IO instruction data is routed through SIDAD for protected guests, so
> adresses do not need to be checked, as this is kernel memory.
> 
> Signed-off-by: Janosch Frank <address@hidden>
> Reviewed-by: Thomas Huth <address@hidden>
> Reviewed-by: David Hildenbrand <address@hidden>
> ---
>  target/s390x/ioinst.c | 33 ++++++++++++++++++++++++++-------
>  1 file changed, 26 insertions(+), 7 deletions(-)
> 
> diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
> index c437a1d8c6afed80..481d789de9e09a04 100644
> --- a/target/s390x/ioinst.c
> +++ b/target/s390x/ioinst.c
> @@ -16,6 +16,23 @@
>  #include "hw/s390x/ioinst.h"
>  #include "trace.h"
>  #include "hw/s390x/s390-pci-bus.h"
> +#include "hw/s390x/pv.h"
> +

Maybe add

/* all I/O instructions but chsc use the s format */

to emphasize that this is not a generic decoder?

> +static uint64_t get_address_from_regs(CPUS390XState *env, uint32_t ipb,
> +                                      uint8_t *ar)
> +{
> +    /*
> +     * Addresses for protected guests are all offsets into the
> +     * satellite block which holds the IO control structures. Those
> +     * control structures are always aligned and accessible, so we can
> +     * return 0 here which will pass the following address checks.
> +     */
> +    if (s390_is_pv()) {
> +        *ar = 0;
> +        return 0;
> +    }
> +    return decode_basedisp_s(env, ipb, ar);
> +}
>  
>  int ioinst_disassemble_sch_ident(uint32_t value, int *m, int *cssid, int 
> *ssid,
>                                   int *schid)

With the other comment updates,

Reviewed-by: Cornelia Huck <address@hidden>