Re: [RESEND PATCH 01/32] memory: Add RAM_PROTECTED flag to skip IOMMU mappings

[Yang Zhong <yang.zhong@intel.com>]

On Fri, May 07, 2021 at 02:45:21PM +0200, Paolo Bonzini wrote:
> On 07/05/21 07:24, Yang Zhong wrote:
> >   Paolo, i will revert this patch, but in order to disable sgx epc memory region
> >   as DMA target, we still need to skip this memory region while adding this memory
> >   region.
> >
> >   So, my plan is to revert this patch, and then add one new bool variable in the
> >   struct MemoryRegion.
> >
> >   The new patch as below and it will be as patch 2 in the next version
> >
> >   diff --git a/backends/hostmem-epc.c b/backends/hostmem-epc.c
> >   index 0c98812f0d..316e1ee688 100644
> >   --- a/backends/hostmem-epc.c
> >   +++ b/backends/hostmem-epc.c
> >   @@ -67,6 +67,7 @@ void sgx_memory_backend_reset(HostMemoryBackend *backend, int fd,
> >        }
> >
> >        sgx_epc_backend_memory_alloc(backend, errp);
> >   +    mr->sgx_epc_device = true;
> >   }
> >
> >   static void sgx_epc_backend_instance_init(Object *obj)
> >   diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> >   index 5bc5d29358..7a53855436 100644
> >   --- a/hw/vfio/common.c
> >   +++ b/hw/vfio/common.c
> >   @@ -538,7 +538,7 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> >    {
> >        return (!memory_region_is_ram(section->mr) &&
> >                !memory_region_is_iommu(section->mr)) ||
> >   +            section->mr->sgx_epc_device ||
> >                /*
> >                 * Sizing an enabled 64-bit BAR can cause spurious mappings to
> >                 * addresses in the upper part of the 64-bit address space.  These
> >    diff --git a/include/exec/memory.h b/include/exec/memory.h
> >    index 2816e52be3..9bba0a1590 100644
> >    --- a/include/exec/memory.h
> >    +++ b/include/exec/memory.h
> >    @@ -463,6 +463,7 @@ struct MemoryRegion {
> >         bool readonly; /* For RAM regions */
> >         bool nonvolatile;
> >         bool rom_device;
> >    +    bool sgx_epc_device;
> >         bool flush_coalesced_mmio;
> >         uint8_t dirty_log_mask;
> >         bool is_iommu;
> >   If this patch is not suitable to skip this memory region, any suggestion is
> >   appreciated, thanks!
> 
> No, you can keep RAM_PROTECTED.  I was just remarking on the new
> bool argument, and suggesting passing the flags (RAM_SHARED and
> RAM_PROTECTED) directly  tot he memory_region_init* functions.
>

  Paolo, thanks! If there is no new comments from community, i will send the V2
  in the next week. thanks!

  Yang


 
> Paolo