[PATCH v7 4/9] x86/hyperv/vtl: Set real_mode_header in hv_vtl_init_platform()

[Ricardo Neri <ricardo.neri-calderon@linux.intel.com>]

From: Yunhong Jiang <yunhong.jiang@linux.intel.com>

Hyper-V VTL clears x86_platform.realmode_{init(), reserve()} in
hv_vtl_init_platform() whereas it sets real_mode_header later in
hv_vtl_early_init(). There is no need to deal with the settings of real
mode memory in two places. Also, both functions are called much earlier
than x86_platform.realmode_init() (via an early_initcall), where the
real_mode_header is needed.

Set real_mode_header in hv_vtl_init_platform() to keep all code dealing
with memory for the real mode trampoline in one place. Besides making the
code more readable, it prepares it for a subsequent changeset in which the
behavior needs to change to support Hyper-V VTL guests in TDX a
environment.

Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
Changes in v7:
 - None

Changes in v6:
 - Corrected reference to hv_vtl_init_platform() in the changelog.
   (Dexuan)
 - Added Reviewed-by tag from Dexuan. Thanks!

Changes in v5:
 - None

Changes in v4:
 - Added Reviewed-by tag from Michael. Thanks!

Changes in v3:
 - Edited the commit message for clarity.

Changes in v2:
 - Introduced this patch.
---
 arch/x86/hyperv/hv_vtl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index 042e8712d8de..e10b63b7a49f 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -65,6 +65,7 @@ void __init hv_vtl_init_platform(void)
 
 	x86_platform.realmode_reserve = x86_init_noop;
 	x86_platform.realmode_init = x86_init_noop;
+	real_mode_header = &hv_vtl_real_mode_header;
 	x86_init.irqs.pre_vector_init = x86_init_noop;
 	x86_init.timers.timer_init = x86_init_noop;
 	x86_init.resources.probe_roms = x86_init_noop;
@@ -244,7 +245,6 @@ int __init hv_vtl_early_init(void)
 		panic("XSAVE has to be disabled as it is not supported by this module.\n"
 			  "Please add 'noxsave' to the kernel command line.\n");
 
-	real_mode_header = &hv_vtl_real_mode_header;
 	apic_update_callback(wakeup_secondary_cpu_64, hv_vtl_wakeup_secondary_cpu);
 
 	return 0;

-- 
2.43.0