Attachment 295030 Details for Bug 430938 – xen change freq hypercall

[patch] xen change freq hypercall

RHEL5.2_Xen_change_freq_hypercall.patch (text/plain), 1.94 KB, created by Bhavna Sarathy on 2008-02-15 18:41:41 UTC

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Creator: Bhavna Sarathy

Created: 2008-02-15 18:41:41 UTC

Size: 1.94 KB

patch

obsolete

>Resolves BZ 430938
>
>Fix XENPF_change_freq hypercall to not dereference a non-existent
>stack variable. Also sanity check (slightly) the frequency argument to
>cpu_frequency_change().
>
>--- xen/arch/x86/platform_hypercall.c.fixhypercallorig	2008-02-06 16:48:46.000000000 -0500
>+++ xen/arch/x86/platform_hypercall.c	2008-02-06 16:49:17.000000000 -0500
>@@ -40,9 +40,11 @@ DEFINE_SPINLOCK(xenpf_lock);
> extern spinlock_t xenpf_lock;
> #endif
> 
>+static DEFINE_PER_CPU(uint64_t, freq);
>+
> static long cpu_frequency_change_helper(void *data)
> {
>-    return cpu_frequency_change(*(uint64_t *)data);
>+    return cpu_frequency_change(this_cpu(freq));
> }
> 
> ret_t do_platform_op(XEN_GUEST_HANDLE(xen_platform_op_t) u_xenpf_op)
>@@ -270,11 +272,12 @@ ret_t do_platform_op(XEN_GUEST_HANDLE(xe
>         if ( cpufreq_controller != FREQCTL_dom0_kernel )
>             break;
>         ret = -EINVAL;
>-        if ( op->u.change_freq.flags != 0 )
>+        if ( op->u.change_freq.flags || !cpu_online(op->u.change_freq.cpu) )
>             break;
>+        per_cpu(freq, op->u.change_freq.cpu) = op->u.change_freq.freq;
>         ret = continue_hypercall_on_cpu(op->u.change_freq.cpu,
>                                         cpu_frequency_change_helper,
>-                                        &op->u.change_freq.freq);
>+                                        NULL);
>         break;
> 
>     case XENPF_getidletime:
>--- xen/arch/x86/time.c.fixhypercallorig	2008-02-06 16:49:02.000000000 -0500
>+++ xen/arch/x86/time.c	2008-02-06 16:49:17.000000000 -0500
>@@ -730,6 +730,14 @@ int cpu_frequency_change(u64 freq)
>     struct cpu_time *t = &this_cpu(cpu_time);
>     u64 curr_tsc;
> 
>+    /* Sanity check: CPU frequency allegedly dropping below 1MHz? */
>+    if ( freq < 1000000u )
>+    {
>+        gdprintk(XENLOG_WARNING, "Rejecting CPU frequency change "
>+                 "to %"PRIu64" Hz.\n", freq);
>+        return -EINVAL;
>+    }
>+
>     local_irq_disable();
>     rdtscll(curr_tsc);
>     t->local_tsc_stamp = curr_tsc;

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