[PATCH v6 03/18] x86/acrn: Introduce acrn_cpuid_base() and hypervisor feature bits

shuo.a.liu
2020-12-01T09:40:57Z

From: Yin Fengwei <fengwei.yin@intel.com>

ACRN Hypervisor reports hypervisor features via CPUID leaf 0x40000001
which is similar to KVM. A VM can check if it's the privileged VM using
the feature bits. The Service VM is the only privileged VM by design.

Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Fengwei Yin <fengwei.yin@intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Yu Wang <yu1.wang@intel.com>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/acrn.h | 16 ++++++++++++++++
arch/x86/kernel/cpu/acrn.c | 2 +-
2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/acrn.h b/arch/x86/include/asm/acrn.h
index ff259b69cde7..127f20672c5d 100644
--- a/arch/x86/include/asm/acrn.h
+++ b/arch/x86/include/asm/acrn.h
@@ -2,7 +2,23 @@
#ifndef _ASM_X86_ACRN_H
#define _ASM_X86_ACRN_H

+/*
+ * This CPUID returns feature bitmaps in EAX.
+ * Guest VM uses this to detect the appropriate feature bit.
+ */
+#define ACRN_CPUID_FEATURES 0x40000001
+/* Bit 0 indicates whether guest VM is privileged */
+#define ACRN_FEATURE_PRIVILEGED_VM BIT(0)
+
void acrn_setup_intr_handler(void (*handler)(void));
void acrn_remove_intr_handler(void);

+static inline u32 acrn_cpuid_base(void)
+{
+ if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+ return hypervisor_cpuid_base("ACRNACRNACRN", 0);
+
+ return 0;
+}
+
#endif /* _ASM_X86_ACRN_H */
diff --git a/arch/x86/kernel/cpu/acrn.c b/arch/x86/kernel/cpu/acrn.c
index e0c181781905..23f5f27b5a02 100644
--- a/arch/x86/kernel/cpu/acrn.c
+++ b/arch/x86/kernel/cpu/acrn.c
@@ -21,7 +21,7 @@

static u32 __init acrn_detect(void)
{
- return hypervisor_cpuid_base("ACRNACRNACRN", 0);
+ return acrn_cpuid_base();
}

static void __init acrn_init_platform(void)
--
2.28.0