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Re: [Qemu-ppc] [PATCH] ppc: add host-serial and host-model machine attri
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-ppc] [PATCH] ppc: add host-serial and host-model machine attributes |
Date: |
Mon, 4 Feb 2019 10:16:42 +0000 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Sat, Feb 02, 2019 at 12:23:58AM +0530, P J P wrote:
> From: Prasad J Pandit <address@hidden>
>
> On ppc hosts, hypervisor shares following system attributes
>
> - /proc/device-tree/system-id
> - /proc/device-tree/model
>
> with a guest. This could lead to information leakage and misuse.[*]
> Add machine attributes to control such system information exposure
> to a guest.
>
> [*] https://wiki.openstack.org/wiki/OSSN/OSSN-0028
>
> Reported-by: Daniel P. Berrangé <address@hidden>
> Fix-suggested-by: Daniel P. Berrangé <address@hidden>
> Signed-off-by: Prasad J Pandit <address@hidden>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 0942f35bf8..b497fe1701 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1249,11 +1249,34 @@ static void *spapr_build_fdt(sPAPRMachineState *spapr,
> * Add info to guest to indentify which host is it being run on
> * and what is the uuid of the guest
> */
> - if (kvmppc_get_host_model(&buf)) {
> + if (machine->host_model && !strcmp(machine->host_model, "none")) {
> + /* -M host-model=none = do not set host-model */
> + } else if (machine->host_model
> + && !strcmp(machine->host_model, "passthrough")) {
> + /* -M host-model=passthrough */
> + _FDT(fdt_setprop_string(fdt, 0, "host-model", buf));
buf hasn't been initialized
> + g_free(buf);
> + } else if (machine->host_model) {
> + /* -M host-model=<user-string> */
> + _FDT(fdt_setprop_string(fdt, 0, "host-model", machine->host_model));
> + } else if (kvmppc_get_host_model(&buf)) {
> + /* -M host-model=xxx attribute not supplied */
> _FDT(fdt_setprop_string(fdt, 0, "host-model", buf));
> g_free(buf);
> }
This structure for the conditionals is a bit unreadable IMHO. It would
be better as a nested if
if (machine->host_model && !g_str_equal(machine->host_model, "none")) {
if (g_str_equal(machine->host_model, "passthrough") {
if (!kvmppc_get_host_model(&buf)) {
... report error...
}
_FDT(fdt_setprop_string(fdt, 0, "host-model", buf));
g_free(buf);
} else {
_FDT(fdt_setprop_string(fdt, 0, "host-model", machine->host_model));
}
}
> - if (kvmppc_get_host_serial(&buf)) {
> +
> + if (machine->host_serial && !strcmp(machine->host_serial, "none")) {
> + /* -M host-serial=none = do not set host-serial */
> + } else if (machine->host_serial
> + && !strcmp(machine->host_serial, "passthrough")) {
> + /* -M host-serial=passthrough */
> + _FDT(fdt_setprop_string(fdt, 0, "host-serial", buf));
> + g_free(buf);
> + } else if (machine->host_serial) {
> + /* -M host-serial=<user-string> */
> + _FDT(fdt_setprop_string(fdt, 0, "host-serial",
> machine->host_serial));
> + } else if (kvmppc_get_host_serial(&buf)) {
> + /* -M host-serial=xxx attribute not supplied */
> _FDT(fdt_setprop_string(fdt, 0, "host-serial", buf));
> g_free(buf);
> }
Same comment for this block.
There's missing logic to set host-model=passthrough for existing machine
types too.
Regards,
Daniel
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