The trampoline_start64 is utilized when the BSP wakes up the APs through
ACPI wakeup mailbox mechanism. Because trampoline_start64 is currently
part of the real model startup code, the real mode memory need to be
reserved.
Signed-off-by: Yunhong Jiang <yunhong.jiang@xxxxxxxxxxxxxxx>
---
arch/x86/hyperv/hv_vtl.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index bfe54afcdf1d..a1eb5548bd4d 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -13,6 +13,7 @@
#include <asm/mshyperv.h>
#include <asm/realmode.h>
#include <../kernel/smpboot.h>
+#include <linux/memblock.h>
extern struct boot_params boot_params;
static struct real_mode_header hv_vtl_real_mode_header;
@@ -34,12 +35,28 @@ static bool hv_is_private_mmio_tdx(u64 addr)
return false;
}
+static void __init hv_reserve_real_mode(void)
+{
+ phys_addr_t mem;
+ size_t size = real_mode_size_needed();
+
+ /*
+ * We only need the memory to be <4GB since the 64-bit trampoline goes
+ * down to 32-bit mode.
+ */
+ mem = memblock_phys_alloc_range(size, PAGE_SIZE, 0, SZ_4G);
+ if (!mem)
+ panic("No sub-4G memory is available for the trampoline\n");
+ set_real_mode_mem(mem);
+}
+
void __init hv_vtl_init_platform(void)
{
pr_info("Linux runs in Hyper-V Virtual Trust Level\n");
if (wakeup_mailbox_addr) {
x86_platform.hyper.is_private_mmio = hv_is_private_mmio_tdx;
+ x86_platform.realmode_reserve = hv_reserve_real_mode;
} else {
x86_platform.realmode_reserve = x86_init_noop;
x86_platform.realmode_init = x86_init_noop;
@@ -259,7 +276,8 @@ 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;
+ if (!wakeup_mailbox_addr)
+ real_mode_header = &hv_vtl_real_mode_header;
apic_update_callback(wakeup_secondary_cpu_64, hv_vtl_wakeup_secondary_cpu);
return 0;
--
2.25.1
