KVM guest: fix bogus wallclock physical address calculation
The use of __pa() to calculate the address of a C-visible symbol
is wrong, and can lead to unpredictable results. See arch/x86/include/asm/page.h
for details.
It should be replaced with __pa_symbol(), that does the correct math here,
by taking relocations into account. This ensures the correct wallclock data
structure physical address is passed to the hypervisor.
Cc: stable@kernel.org
Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 223af43..e5efcdc 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -50,8 +50,8 @@
struct timespec ts;
int low, high;
- low = (int)__pa(&wall_clock);
- high = ((u64)__pa(&wall_clock) >> 32);
+ low = (int)__pa_symbol(&wall_clock);
+ high = ((u64)__pa_symbol(&wall_clock) >> 32);
native_write_msr(MSR_KVM_WALL_CLOCK, low, high);
vcpu_time = &get_cpu_var(hv_clock);