[libvirt][PATCH v4 2/4] qemu: Add command-line to generate SGX EPC memory backend

[Tim Wiederhake]

On Thu, 2021-07-01 at 20:10 +0800, Haibin Huang wrote:
> From: Lin Yang <lin.a.yang at intel.com>
> 
> According to the result parsing from xml, add the argument of
> SGX EPC memory backend into QEMU command line:
> 
>     -object memory-backend-epc,id=mem1,size=<epc_size>K,prealloc \
>     -sgx-epc id=epc1,memdev=mem1
> ---
>  src/qemu/qemu_command.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index 01812cd39b..2c3785886c 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -9869,6 +9869,27 @@ qemuBuildVsockCommandLine(virCommandPtr cmd,
>  }
>  
>  
> +static int
> +qemuBuildSGXCommandLine(virCommandPtr cmd, virDomainSGXDefPtr sgx)
> +{
> +    g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
> +
> +    if (!sgx)
> +        return 0;
> +
> +    VIR_DEBUG("sgx->epc_size=%lluKiB", sgx->epc_size);
> +
> +    virBufferAsprintf(&buf, "memory-backend-
> epc,id=mem1,size=%lluK,prealloc", sgx->epc_size);
> +    virCommandAddArg(cmd, "-object");
> +    virCommandAddArgBuffer(cmd, &buf);

virCommandAddArgFormat?

> +
> +    virCommandAddArg(cmd, "-sgx-epc");
> +    virCommandAddArg(cmd, "id=epc1,memdev=mem1");
> +
> +    return 0;
> +}
> +
> +
>  /*
>   * Constructs a argv suitable for launching qemu with config defined
>   * for a given virtual machine.
> @@ -10154,6 +10175,9 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
>          cfg->logTimestamp)
>          virCommandAddArgList(cmd, "-msg", "timestamp=on", NULL);
>  
> +    if (qemuBuildSGXCommandLine(cmd, def->sgx) < 0)
> +        return NULL;
> +

Personal opinion: I would not add this to the end of the function, but
place it next to the call to "qemuBuildSEVCommandLine(...)". Or replace
the call to qemuBuildSEVCommandLine() with a
"qemuBuildSecurityCommandLine()", which in turn calls
qemuBuild{SEV,SGX}CommandLine().

Regards,
Tim

>      return g_steal_pointer(&cmd);
>  }
>