[PATCH v7 7/9] x86/acpi: Add a helper get the address of the wakeup mailbox

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

A Hyper-V VTL level 2 guest in a TDX environment needs to map the physical
page of the ACPI Multiprocessor Wakeup Structure as private (encrypted). It
needs to know the physical address of this structure. Add a helper function
to retrieve the address.

Suggested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
Changes in v7:
 - Moved the added function to arch/x86/kernel/acpi/madt_wakeup.c
 - Dropped Reviewed-by tags from Dexuan and Michael as this patch
   changed.

Changes in v6:
 - Added Reviewed-by tag from Dexuan. Thanks!

Changes in v5:
 - None

Changes in v4:
 - Renamed function to acpi_get_mp_wakeup_mailbox_paddr().
 - Added Reviewed-by tag from Michael. Thanks!

Changes in v3:
 - Introduced this patch

Changes in v2:
 - N/A
---
 arch/x86/include/asm/acpi.h        | 6 ++++++
 arch/x86/kernel/acpi/madt_wakeup.c | 5 +++++
 2 files changed, 11 insertions(+)

diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 820df375df79..c4e6459bd56b 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -184,6 +184,7 @@ void __iomem *x86_acpi_os_ioremap(acpi_physical_address phys, acpi_size size);
 
 void acpi_setup_mp_wakeup_mailbox(u64 addr);
 struct acpi_madt_multiproc_wakeup_mailbox *acpi_get_mp_wakeup_mailbox(void);
+u64 acpi_get_mp_wakeup_mailbox_paddr(void);
 
 #else /* !CONFIG_ACPI */
 
@@ -210,6 +211,11 @@ static inline struct acpi_madt_multiproc_wakeup_mailbox *acpi_get_mp_wakeup_mail
 	return NULL;
 }
 
+static inline u64 acpi_get_mp_wakeup_mailbox_paddr(void)
+{
+	return 0;
+}
+
 #endif /* !CONFIG_ACPI */
 
 #define ARCH_HAS_POWER_INIT	1
diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c
index 82caf44b45e3..48734e4a6e8f 100644
--- a/arch/x86/kernel/acpi/madt_wakeup.c
+++ b/arch/x86/kernel/acpi/madt_wakeup.c
@@ -258,3 +258,8 @@ struct acpi_madt_multiproc_wakeup_mailbox *acpi_get_mp_wakeup_mailbox(void)
 {
 	return acpi_mp_wake_mailbox;
 }
+
+u64 acpi_get_mp_wakeup_mailbox_paddr(void)
+{
+	return acpi_mp_wake_mailbox_paddr;
+}

-- 
2.43.0