From mboxrd@z Thu Jan  1 00:00:00 1970
From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Subject: Re: [PATCH v6 27/33] nvdimm acpi: support function 0
Date: Fri, 30 Oct 2015 21:01:12 +0800
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Cc: ehabkost@redhat.com, kvm@vger.kernel.org, mst@redhat.com, gleb@kernel.org,
	mtosatti@redhat.com, qemu-devel@nongnu.org, imammedo@redhat.com,
	pbonzini@redhat.com, dan.j.williams@intel.com, rth@twiddle.net
To: Stefan Hajnoczi <stefanha@redhat.com>
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On 10/30/2015 06:14 PM, Stefan Hajnoczi wrote:
> On Fri, Oct 30, 2015 at 01:56:21PM +0800, Xiao Guangrong wrote:
>>   static uint64_t
>>   nvdimm_dsm_read(void *opaque, hwaddr addr, unsigned size)
>>   {
>> -    return 0;
>> +    AcpiNVDIMMState *state = opaque;
>> +    MemoryRegion *dsm_ram_mr = &state->ram_mr;
>> +    NvdimmDsmIn *in;
>> +    GArray *out;
>> +    void *dsm_ram_addr;
>> +    uint32_t buf_size;
>> +
>> +    assert(memory_region_size(dsm_ram_mr) >= sizeof(NvdimmDsmIn));
>> +    dsm_ram_addr = memory_region_get_ram_ptr(dsm_ram_mr);
>> +
>> +    /*
>> +     * The DSM memory is mapped to guest address space so an evil guest
>> +     * can change its content while we are doing DSM emulation. Avoid
>> +     * this by copying DSM memory to QEMU local memory.
>> +     */
>> +    in = g_malloc(memory_region_size(dsm_ram_mr));
>> +    memcpy(in, dsm_ram_addr, memory_region_size(dsm_ram_mr));
>> +
>> +    le32_to_cpus(&in->revision);
>> +    le32_to_cpus(&in->function);
>> +    le32_to_cpus(&in->handle);
>> +
>> +    nvdimm_debug("Revision %#x Handler %#x Function %#x.\n", in->revision,
>> +                 in->handle, in->function);
>> +
>> +    out = g_array_new(false, true /* clear */, 1);
>> +
>> +    if (in->revision != 0x1 /* Current we support DSM Spec Rev1. */) {
>> +        nvdimm_debug("Revision %#x is not supported, expect %#x.\n",
>> +                      in->revision, 0x1);
>> +        nvdimm_dsm_write_status(out, NVDIMM_DSM_STATUS_NOT_SUPPORTED);
>> +        goto exit;
>> +    }
>> +
>> +    /* Handle 0 is reserved for NVDIMM Root Device. */
>> +    if (!in->handle) {
>> +        nvdimm_dsm_root(in, out);
>> +        goto exit;
>> +    }
>> +
>> +    nvdimm_dsm_device(in, out);
>> +
>> +exit:
>> +    /* Write output result to dsm memory. */
>> +    memcpy(dsm_ram_addr, out->data, out->len);
>> +    memory_region_set_dirty(dsm_ram_mr, 0, out->len);
>
> If you respin this series, please add this before the memcpy out:
>
>    assert(out->len <= memory_region_size(dsm_ram_mr))
>
> That way we can catch situations where too much output data was
> generated by mistake.
>

Okay. If this patchset is okay to be merged, i will add this in
future development.

Thanks for your continuous and active review, Stefan!