Re: [Qemu-devel] [PATCH] pseries: Allow TCG h_enter to work with hotplugged memory

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 01/21/2016 12:41 PM, David Gibson wrote:
> The implementation of the H_ENTER hypercall for PAPR guests needs to
> enforce correct access attributes on the inserted HPTE.  This means
> determining if the HPTE's real address is a regular RAM address (which
> requires attributes for coherent access) or an IO address (which requires
> attributes for cache-inhibited access).
>
> At the moment this check is implemented with (raddr < machine->ram_size),
> but that only handles addresses in the base RAM area, not any hotplugged
> RAM.
>
> This patch corrects the problem with a new helper.
>
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>


Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>



> ---
>   hw/ppc/spapr_hcall.c | 19 +++++++++++++++++--
>   1 file changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index cebceea..ea33bc7 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -84,10 +84,25 @@ static inline bool valid_pte_index(CPUPPCState *env, target_ulong pte_index)
>       return true;
>   }
>
> +static bool is_ram_address(sPAPRMachineState *spapr, hwaddr addr)
> +{
> +    MachineState *machine = MACHINE(spapr);
> +    MemoryHotplugState *hpms = &spapr->hotplug_memory;
> +
> +    if (addr < machine->ram_size) {
> +        return true;
> +    }
> +    if ((addr >= hpms->base)
> +        && ((addr - hpms->base) < memory_region_size(&hpms->mr))) {
> +        return true;
> +    }
> +
> +    return false;
> +}
> +
>   static target_ulong h_enter(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>                               target_ulong opcode, target_ulong *args)
>   {
> -    MachineState *machine = MACHINE(spapr);
>       CPUPPCState *env = &cpu->env;
>       target_ulong flags = args[0];
>       target_ulong pte_index = args[1];
> @@ -119,7 +134,7 @@ static target_ulong h_enter(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>
>       raddr = (ptel & HPTE64_R_RPN) & ~((1ULL << page_shift) - 1);
>
> -    if (raddr < machine->ram_size) {
> +    if (is_ram_address(spapr, raddr)) {
>           /* Regular RAM - should have WIMG=0010 */
>           if ((ptel & HPTE64_R_WIMG) != HPTE64_R_M) {
>               return H_PARAMETER;
>


-- 
Alexey