[PATCH v3 08/13] x86/hyperv/vtl: Set real_mode_header in hv_vtl_init_platform()

Ricardo Neri
2025-05-03T19:10:17Z

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

Hyper-V VTL clears x86_platform.realmode_{init(), reserve()} in
hv_vtl_platform_init() whereas it sets real_mode_header later in
hv_vtl_early_init(). There is no need to deal with the real mode memory
in two places: x86_platform.realmode_init() is invoked much later via an
early_initcall.

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 environment.

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 since v2:
- Edited the commit message for clarity.

Changes since v1:
- 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 4580936dcb03..6bd183ee484f 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -60,6 +60,7 @@ 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;
@@ -279,7 +280,6 @@ 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