linux-kernel - [PATCH 5/7] x86/hyperv: Mark ACPI wakeup mailbox page as private

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Message-Id: <20240806221237.1634126-6-yunhong.jiang@linux.intel.com>
Date: Tue,  6 Aug 2024 15:12:35 -0700
From: Yunhong Jiang <yunhong.jiang@...ux.intel.com>
To: tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com,
	x86@...nel.org,
	hpa@...or.com,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org,
	kys@...rosoft.com,
	haiyangz@...rosoft.com,
	wei.liu@...nel.org,
	decui@...rosoft.com,
	rafael@...nel.org,
	lenb@...nel.org,
	kirill.shutemov@...ux.intel.com
Cc: linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-hyperv@...r.kernel.org,
	linux-acpi@...r.kernel.org,
	yunhong.jiang@...ux.intel.com
Subject: [PATCH 5/7] x86/hyperv: Mark ACPI wakeup mailbox page as private

The ACPI wakeup mailbox is accessed by the OS and the firmware, both are
in the guest's context, instead of the hypervisor/VMM context. Mark the
address private explicitly.

Signed-off-by: Yunhong Jiang <yunhong.jiang@...ux.intel.com>
---
 arch/x86/hyperv/hv_vtl.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index 04775346369c..bfe54afcdf1d 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -22,12 +22,28 @@ static bool __init hv_vtl_msi_ext_dest_id(void)
 	return true;
 }
 
+/*
+ * The ACPI wakeup mailbox are accessed by the OS and the BIOS, both are in the
+ * guest's context, instead of the hypervisor/VMM context.
+ */
+static bool hv_is_private_mmio_tdx(u64 addr)
+{
+	if (wakeup_mailbox_addr && (addr >= wakeup_mailbox_addr &&
+	    addr < (wakeup_mailbox_addr + PAGE_SIZE)))
+		return true;
+	return false;
+}
+
 void __init hv_vtl_init_platform(void)
 {
 	pr_info("Linux runs in Hyper-V Virtual Trust Level\n");
 
-	x86_platform.realmode_reserve = x86_init_noop;
-	x86_platform.realmode_init = x86_init_noop;
+	if (wakeup_mailbox_addr) {
+		x86_platform.hyper.is_private_mmio = hv_is_private_mmio_tdx;
+	} else {
+		x86_platform.realmode_reserve = x86_init_noop;
+		x86_platform.realmode_init = x86_init_noop;
+	}
 	x86_init.irqs.pre_vector_init = x86_init_noop;
 	x86_init.timers.timer_init = x86_init_noop;
 
-- 
2.25.1