From: Jinank Jain <jinankjain@linux.microsoft.com>
To: jinankjain@microsoft.com
Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org,
decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org,
hpa@zytor.com, arnd@arndb.de, peterz@infradead.org,
jpoimboe@kernel.org, jinankjain@linux.microsoft.com,
seanjc@google.com, kirill.shutemov@linux.intel.com,
ak@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, anrayabh@linux.microsoft.com,
mikelley@microsoft.com
Subject: [PATCH v4 1/5] x86/hyperv: Add support for detecting nested hypervisor
Date: Thu, 17 Nov 2022 03:27:54 +0000 [thread overview]
Message-ID: <08ab7aede41f2feb1cd8ac21d0ddd17e25b1d070.1668618583.git.jinankjain@linux.microsoft.com> (raw)
In-Reply-To: <cover.1668618583.git.jinankjain@linux.microsoft.com>
When Linux runs as a root partition for Microsoft Hypervisor. It is
possible to detect if it is running as nested hypervisor using
hints exposed by mshv. While at it expose a new variable called
hv_nested which can be used later for making decisions specific to
nested use case.
Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
---
arch/arm64/hyperv/mshyperv.c | 6 ++++++
arch/x86/include/asm/hyperv-tlfs.h | 3 +++
arch/x86/kernel/cpu/mshyperv.c | 7 +++++++
drivers/hv/hv_common.c | 7 +++++--
include/asm-generic/mshyperv.h | 1 +
5 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
index a406454578f0..2024b19dc514 100644
--- a/arch/arm64/hyperv/mshyperv.c
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -19,6 +19,9 @@
static bool hyperv_initialized;
+/* Is Linux running on nested Microsoft Hypervisor */
+bool hv_nested;
+
static int __init hyperv_init(void)
{
struct hv_get_vp_registers_output result;
@@ -63,6 +66,9 @@ static int __init hyperv_init(void)
pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
b >> 16, b & 0xFFFF, a, d & 0xFFFFFF, c, d >> 24);
+ /* ARM64 does not support nested virtualization */
+ hv_nested = false;
+
ret = hv_common_init();
if (ret)
return ret;
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 6d9368ea3701..58c03d18c235 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -114,6 +114,9 @@
/* Recommend using the newer ExProcessorMasks interface */
#define HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED BIT(11)
+/* Indicates that the hypervisor is nested within a Hyper-V partition. */
+#define HV_X64_HYPERV_NESTED BIT(12)
+
/* Recommend using enlightened VMCS */
#define HV_X64_ENLIGHTENED_VMCS_RECOMMENDED BIT(14)
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 831613959a92..9a4204139490 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -37,6 +37,8 @@
/* Is Linux running as the root partition? */
bool hv_root_partition;
+/* Is Linux running on nested Microsoft Hypervisor */
+bool hv_nested;
struct ms_hyperv_info ms_hyperv;
#if IS_ENABLED(CONFIG_HYPERV)
@@ -301,6 +303,11 @@ static void __init ms_hyperv_init_platform(void)
pr_info("Hyper-V: running as root partition\n");
}
+ if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) {
+ hv_nested = true;
+ pr_info("Hyper-V: running on a nested hypervisor\n");
+ }
+
/*
* Extract host information.
*/
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index ae68298c0dca..dcb336ce374f 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -25,8 +25,8 @@
#include <asm/mshyperv.h>
/*
- * hv_root_partition and ms_hyperv are defined here with other Hyper-V
- * specific globals so they are shared across all architectures and are
+ * hv_root_partition, ms_hyperv and hv_nested are defined here with other
+ * Hyper-V specific globals so they are shared across all architectures and are
* built only when CONFIG_HYPERV is defined. But on x86,
* ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not
* defined, and it uses these two variables. So mark them as __weak
@@ -36,6 +36,9 @@
bool __weak hv_root_partition;
EXPORT_SYMBOL_GPL(hv_root_partition);
+bool __weak hv_nested;
+EXPORT_SYMBOL_GPL(hv_nested);
+
struct ms_hyperv_info __weak ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index bfb9eb9d7215..5df6e944e6a9 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -164,6 +164,7 @@ extern int vmbus_interrupt;
extern int vmbus_irq;
extern bool hv_root_partition;
+extern bool hv_nested;
#if IS_ENABLED(CONFIG_HYPERV)
/*
--
2.25.1
next prev parent reply other threads:[~2022-11-17 3:28 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <https://lore.kernel.org/linux-hyperv/cover.1667394408.git.jinankjain@microsoft.com/T/#t>
2022-11-02 16:35 ` [PATCH v2 0/5] Add support running nested Microsoft Hypervisor Jinank Jain
2022-11-02 16:35 ` [PATCH v2 1/5] mshv: Add support for detecting nested hypervisor Jinank Jain
2022-11-03 3:29 ` Michael Kelley (LINUX)
2022-11-02 16:35 ` [PATCH v2 2/5] hv: Setup synic registers in case of nested root partition Jinank Jain
2022-11-03 3:29 ` Michael Kelley (LINUX)
2022-11-02 16:36 ` [PATCH v2 3/5] hv: Add an interface to do nested hypercalls Jinank Jain
2022-11-03 3:30 ` Michael Kelley (LINUX)
2022-11-02 16:36 ` [PATCH v2 4/5] hv: Enable vmbus driver for nested root partition Jinank Jain
2022-11-03 3:30 ` Michael Kelley (LINUX)
2022-11-03 14:16 ` Wei Liu
2022-11-03 7:02 ` Anirudh Rayabharam
2022-11-02 16:36 ` [PATCH v2 5/5] hv, mshv : Change interrupt vector " Jinank Jain
2022-11-17 3:27 ` [PATCH v4 0/5] Add support running nested Microsoft Hypervisor Jinank Jain
2022-11-17 3:27 ` Jinank Jain [this message]
2022-11-18 15:24 ` [PATCH v4 1/5] x86/hyperv: Add support for detecting nested hypervisor Michael Kelley (LINUX)
2022-11-17 3:27 ` [PATCH v4 2/5] Drivers: hv: Setup synic registers in case of nested root partition Jinank Jain
2022-11-18 15:34 ` Michael Kelley (LINUX)
2022-11-19 1:39 ` Nuno Das Neves
2022-11-17 3:27 ` [PATCH v4 3/5] x86/hyperv: Add an interface to do nested hypercalls Jinank Jain
2022-11-18 15:35 ` Michael Kelley (LINUX)
2022-11-17 3:27 ` [PATCH v4 4/5] Drivers: hv: Enable vmbus driver for nested root partition Jinank Jain
2022-11-18 15:36 ` Michael Kelley (LINUX)
2022-11-17 3:27 ` [PATCH v4 5/5] x86/hyperv: Change interrupt vector " Jinank Jain
2022-11-18 15:41 ` Michael Kelley (LINUX)
2022-11-24 6:02 ` [PATCH v6 0/5] Add support running nested Microsoft Hypervisor Jinank Jain
2022-11-24 6:02 ` [PATCH v6 1/5] x86/hyperv: Add support for detecting nested hypervisor Jinank Jain
2022-11-24 6:02 ` [PATCH v6 2/5] Drivers: hv: Setup synic registers in case of nested root partition Jinank Jain
2022-11-28 19:45 ` Michael Kelley (LINUX)
2022-11-24 6:02 ` [PATCH v6 3/5] x86/hyperv: Add an interface to do nested hypercalls Jinank Jain
2022-11-24 6:02 ` [PATCH v6 4/5] Drivers: hv: Enable vmbus driver for nested root partition Jinank Jain
2022-11-24 6:02 ` [PATCH v6 5/5] x86/hyperv: Change interrupt vector " Jinank Jain
2022-12-01 11:03 ` [PATCH v7 0/5] Add support running nested Microsoft Hypervisor Jinank Jain
2022-12-01 11:03 ` [PATCH v7 1/5] x86/hyperv: Add support for detecting nested hypervisor Jinank Jain
2022-12-01 11:03 ` [PATCH v7 2/5] Drivers: hv: Setup synic registers in case of nested root partition Jinank Jain
2022-12-02 4:00 ` Michael Kelley (LINUX)
2022-12-02 7:05 ` Jinank Jain
2022-12-02 15:27 ` Michael Kelley (LINUX)
2022-12-01 11:03 ` [PATCH v7 3/5] x86/hyperv: Add an interface to do nested hypercalls Jinank Jain
2022-12-01 11:03 ` [PATCH v7 4/5] Drivers: hv: Enable vmbus driver for nested root partition Jinank Jain
2022-12-01 11:03 ` [PATCH v7 5/5] x86/hyperv: Change interrupt vector " Jinank Jain
2022-12-09 5:32 ` [PATCH v8 0/5] Add support running nested Microsoft Hypervisor Jinank Jain
2022-12-09 5:32 ` [PATCH v8 1/5] x86/hyperv: Add support for detecting nested hypervisor Jinank Jain
2022-12-09 17:58 ` Nuno Das Neves
2022-12-09 5:32 ` [PATCH v8 2/5] Drivers: hv: Setup synic registers in case of nested root partition Jinank Jain
2022-12-09 17:56 ` Michael Kelley (LINUX)
2022-12-09 5:32 ` [PATCH v8 3/5] x86/hyperv: Add an interface to do nested hypercalls Jinank Jain
2022-12-09 18:16 ` Nuno Das Neves
2022-12-09 5:32 ` [PATCH v8 4/5] Drivers: hv: Enable vmbus driver for nested root partition Jinank Jain
2022-12-09 18:16 ` Nuno Das Neves
2022-12-09 5:32 ` [PATCH v8 5/5] x86/hyperv: Change interrupt vector " Jinank Jain
2022-12-14 6:32 ` [PATCH v9 0/5] Add support running nested Microsoft Hypervisor Jinank Jain
2022-12-14 6:33 ` [PATCH v9 1/5] x86/hyperv: Add support for detecting nested hypervisor Jinank Jain
2022-12-14 6:33 ` [PATCH v9 2/5] Drivers: hv: Setup synic registers in case of nested root partition Jinank Jain
2022-12-29 20:57 ` Michael Kelley (LINUX)
2022-12-14 6:33 ` [PATCH v9 3/5] x86/hyperv: Add an interface to do nested hypercalls Jinank Jain
2022-12-14 17:25 ` Nuno Das Neves
2022-12-14 6:33 ` [PATCH v9 4/5] Drivers: hv: Enable vmbus driver for nested root partition Jinank Jain
2022-12-14 6:33 ` [PATCH v9 5/5] x86/hyperv: Change interrupt vector " Jinank Jain
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