[Qemu-devel] Re: [PATCH 07/10] Add RAM -> physical addr mapping in MCE simulation

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 10/20/2010 12:43 PM, Marcelo Tosatti wrote:
> From: Huang Ying<ying.huang@intel.com>
>
> In QEMU-KVM, physical address != RAM address. While MCE simulation
> needs physical address instead of RAM address. So
> kvm_physical_memory_addr_from_ram() is implemented to do the
> conversion, and it is invoked before being filled in the IA32_MCi_ADDR
> MSR.
>
> Reported-by: Dean Nelson<dnelson@redhat.com>
> Signed-off-by: Huang Ying<ying.huang@intel.com>
> Signed-off-by: Marcelo Tosatti<mtosatti@redhat.com>
> Signed-off-by: Avi Kivity<avi@redhat.com>
> ---
>   kvm-all.c |   18 ++++++++++++++++++
>   kvm.h     |    6 ++++++
>   2 files changed, 24 insertions(+), 0 deletions(-)
>
> diff --git a/kvm-all.c b/kvm-all.c
> index 1cc696f..37b99c7 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -137,6 +137,24 @@ static KVMSlot *kvm_lookup_overlapping_slot(KVMState *s,
>       return found;
>   }
>
> +int kvm_physical_memory_addr_from_ram(KVMState *s, ram_addr_t ram_addr,
> +                                      target_phys_addr_t *phys_addr)
> +{
> +    int i;
> +
> +    for (i = 0; i<  ARRAY_SIZE(s->slots); i++) {
> +        KVMSlot *mem =&s->slots[i];
> +
> +        if (ram_addr>= mem->phys_offset&&
> +            ram_addr<  mem->phys_offset + mem->memory_size) {
> +            *phys_addr = mem->start_addr + (ram_addr - mem->phys_offset);
> +            return 1;
> +        }
> +    }
>    

This is bogus.

There isn't one mapping from ram_addr_t to target_phys_addr_t.  There 
may be many because or RAM aliasing.

Using KVMSlot is also wrong.  This is a function that belongs in exec.c.

Regards,

Anthony Liguori

> +    return 0;
> +}
> +
>   static int kvm_set_user_memory_region(KVMState *s, KVMSlot *slot)
>   {
>       struct kvm_userspace_memory_region mem;
> diff --git a/kvm.h b/kvm.h
> index 50b6c01..b2fb3af 100644
> --- a/kvm.h
> +++ b/kvm.h
> @@ -174,6 +174,12 @@ static inline void cpu_synchronize_post_init(CPUState *env)
>       }
>   }
>
> +
> +#if !defined(CONFIG_USER_ONLY)
> +int kvm_physical_memory_addr_from_ram(KVMState *s, ram_addr_t ram_addr,
> +                                      target_phys_addr_t *phys_addr);
> +#endif
> +
>   #endif
>   int kvm_set_ioeventfd_mmio_long(int fd, uint32_t adr, uint32_t val, bool assign);
>
>