Drivers: hv: restore hypervcall page cleanup before kexec
We need to cleanup the hypercall page before doing kexec/kdump or the new
kernel may crash if it tries to use it. Reuse the now-empty hv_cleanup
function renaming it to hyperv_cleanup and moving to the arch specific
code.
Fixes: 8730046c1498 ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index d289bc2..d6b018b 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -166,6 +166,22 @@ void hyperv_init(void)
}
/*
+ * This routine is called before kexec/kdump, it does the required cleanup.
+ */
+void hyperv_cleanup(void)
+{
+ union hv_x64_msr_hypercall_contents hypercall_msr;
+
+ /* Reset our OS id */
+ wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
+
+ /* Reset the hypercall page */
+ hypercall_msr.as_uint64 = 0;
+ wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+}
+EXPORT_SYMBOL_GPL(hyperv_cleanup);
+
+/*
* hv_do_hypercall- Invoke the specified hypercall
*/
u64 hv_do_hypercall(u64 control, void *input, void *output)
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 42505d1..f8dc370 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -171,5 +171,6 @@ void hv_remove_crash_handler(void);
void hyperv_init(void);
void hyperv_report_panic(struct pt_regs *regs);
bool hv_is_hypercall_page_setup(void);
+void hyperv_cleanup(void);
#endif
#endif