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>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20240726225910.1912537-2-romank@linux.microsoft.com>
Date: Fri, 26 Jul 2024 15:59:04 -0700
From: Roman Kisel <romank@...ux.microsoft.com>
To: arnd@...db.de,
	bhelgaas@...gle.com,
	bp@...en8.de,
	catalin.marinas@....com,
	dave.hansen@...ux.intel.com,
	decui@...rosoft.com,
	haiyangz@...rosoft.com,
	hpa@...or.com,
	kw@...ux.com,
	kys@...rosoft.com,
	lenb@...nel.org,
	lpieralisi@...nel.org,
	mingo@...hat.com,
	rafael@...nel.org,
	robh@...nel.org,
	tglx@...utronix.de,
	wei.liu@...nel.org,
	will@...nel.org,
	linux-acpi@...r.kernel.org,
	linux-arch@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-hyperv@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org,
	x86@...nel.org
Cc: apais@...rosoft.com,
	benhill@...rosoft.com,
	ssengar@...rosoft.com,
	sunilmut@...rosoft.com,
	vdso@...bites.dev
Subject: [PATCH v3 1/7] arm64: hyperv: Use SMC to detect hypervisor presence

The arm64 Hyper-V startup path relies on ACPI to detect
running under a Hyper-V compatible hypervisor. That
doesn't work on non-ACPI systems.

Hoist the ACPI detection logic into a separate function,
use the new SMC added recently to Hyper-V to use in the
non-ACPI case.

Signed-off-by: Roman Kisel <romank@...ux.microsoft.com>
---
 arch/arm64/hyperv/mshyperv.c      | 36 ++++++++++++++++++++++++++-----
 arch/arm64/include/asm/mshyperv.h |  5 +++++
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
index b1a4de4eee29..341f98312667 100644
--- a/arch/arm64/hyperv/mshyperv.c
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -27,6 +27,34 @@ int hv_get_hypervisor_version(union hv_hypervisor_version_info *info)
 	return 0;
 }
 
+static bool hyperv_detect_via_acpi(void)
+{
+	if (acpi_disabled)
+		return false;
+#if IS_ENABLED(CONFIG_ACPI)
+	/* Hypervisor ID is only available in ACPI v6+. */
+	if (acpi_gbl_FADT.header.revision < 6)
+		return false;
+	return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) == 0;
+#else
+	return false;
+#endif
+}
+
+static bool hyperv_detect_via_smc(void)
+{
+	struct arm_smccc_res res = {};
+
+	if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC)
+		return false;
+	arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
+
+	return res.a0 == ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_0 &&
+		res.a1 == ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_1 &&
+		res.a2 == ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_2 &&
+		res.a3 == ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_3;
+}
+
 static int __init hyperv_init(void)
 {
 	struct hv_get_vp_registers_output	result;
@@ -35,13 +63,11 @@ static int __init hyperv_init(void)
 
 	/*
 	 * Allow for a kernel built with CONFIG_HYPERV to be running in
-	 * a non-Hyper-V environment, including on DT instead of ACPI.
+	 * a non-Hyper-V environment.
+	 *
 	 * In such cases, do nothing and return success.
 	 */
-	if (acpi_disabled)
-		return 0;
-
-	if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8))
+	if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smc())
 		return 0;
 
 	/* Setup the guest ID */
diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
index a975e1a689dd..a7a3586f7cb1 100644
--- a/arch/arm64/include/asm/mshyperv.h
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -51,4 +51,9 @@ static inline u64 hv_get_msr(unsigned int reg)
 
 #include <asm-generic/mshyperv.h>
 
+#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_0	0x7948734d
+#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_1	0x56726570
+#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_2	0
+#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_3	0
+
 #endif
-- 
2.34.1


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ