linux-kernel - [PATCH 3/5] x86/hyperv: Don't use auto-eoi when Secure AVIC is available

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20250918150023.474021-4-tiala@microsoft.com>
Date: Thu, 18 Sep 2025 11:00:21 -0400
From: Tianyu Lan <ltykernel@...il.com>
To: kys@...rosoft.com,
	haiyangz@...rosoft.com,
	wei.liu@...nel.org,
	decui@...rosoft.com,
	tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com,
	x86@...nel.org,
	hpa@...or.com,
	arnd@...db.de,
	Neeraj.Upadhyay@....com,
	tiala@...rosoft.com,
	kvijayab@....com,
	romank@...ux.microsoft.com
Cc: linux-arch@...r.kernel.org,
	linux-hyperv@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Michael Kelley <mhklinux@...look.com>
Subject: [PATCH 3/5] x86/hyperv: Don't use auto-eoi when Secure AVIC is available

Hyper-V doesn't support auto-eoi with Secure AVIC.
So set the HV_DEPRECATING_AEOI_RECOMMENDED flag
to force writing the EOI register after handling an interrupt.

Reviewed-by: Michael Kelley <mhklinux@...look.com>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@....com>
Signed-off-by: Tianyu Lan <tiala@...rosoft.com>
---
 arch/x86/kernel/cpu/mshyperv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index c78f860419d6..6dd3ae66a646 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -464,6 +464,9 @@ static void __init ms_hyperv_init_platform(void)
 
 	hv_identify_partition_type();
 
+	if (cc_platform_has(CC_ATTR_SNP_SECURE_AVIC))
+		ms_hyperv.hints |= HV_DEPRECATING_AEOI_RECOMMENDED;
+
 	if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) {
 		hv_nested = true;
 		pr_info("Hyper-V: running on a nested hypervisor\n");
-- 
2.25.1