register an nmi callback. And this callback does busy-loop on threads
which are waiting for loading completion if 'loading_ucode' is true.
Signed-off-by: Chao Gao <chao....@intel.com>
---
Changes in v8:
- new
---
xen/arch/x86/microcode.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index 67549be..4ac7e93 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -38,6 +38,7 @@
#include <asm/delay.h>
#include <asm/msr.h>
+#include <asm/nmi.h>
#include <asm/processor.h>
#include <asm/setup.h>
#include <asm/microcode.h>
@@ -439,12 +440,37 @@ static int do_microcode_update(void *patch)
return ret;
}
+static int microcode_nmi_callback(const struct cpu_user_regs *regs, int cpu)
+{
+ bool print = false;
+
+ /* The first thread of a core is to load an update. Don't block it. */
+ if ( cpu == cpumask_first(per_cpu(cpu_sibling_mask, cpu)) )
+ return 0;
+
+ if ( loading_state == LOADING_ENTERED )
+ {
+ cpumask_set_cpu(cpu, &cpu_callin_map);
+ printk(XENLOG_DEBUG "CPU%u enters %s\n", smp_processor_id(), __func__);
+ print = true;
+ }
+
+ while ( loading_state == LOADING_ENTERED )
+ rep_nop();
+
+ if ( print )
+ printk(XENLOG_DEBUG "CPU%u exits %s\n", smp_processor_id(), __func__);
+
+ return 0;
+}
+
int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void) buf, unsigned long len)
{
int ret;
void *buffer;
unsigned int cpu, updated;
struct microcode_patch *patch;
+ nmi_callback_t *saved_nmi_callback;
if ( len != (uint32_t)len )
return -E2BIG;
@@ -509,6 +535,8 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void)
buf, unsigned long len)
* watchdog timeout.
*/
watchdog_disable();
+
+ saved_nmi_callback = set_nmi_callback(microcode_nmi_callback);
/*
* Late loading dance. Why the heavy-handed stop_machine effort?
*
@@ -521,6 +549,7 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void)
buf, unsigned long len)
* conservative and good.
*/
ret = stop_machine_run(do_microcode_update, patch, NR_CPUS);
+ set_nmi_callback(saved_nmi_callback);
watchdog_enable();
updated = atomic_read(&cpu_updated);
--
1.8.3.1
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
