[PATCH v2 1/7] hyperv: Detect Nested virtualization support for SVM

Vineeth Pillai
2021-04-15T13:44:11Z

Detect nested features exposed by Hyper-V if SVM is enabled.

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
---
arch/x86/kernel/cpu/mshyperv.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 3546d3e21787..c6f812851e37 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -252,6 +252,7 @@ static void __init hv_smp_prepare_cpus(unsigned int max_cpus)

static void __init ms_hyperv_init_platform(void)
{
+ int hv_max_functions_eax;
int hv_host_info_eax;
int hv_host_info_ebx;
int hv_host_info_ecx;
@@ -269,6 +270,8 @@ static void __init ms_hyperv_init_platform(void)
ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);

+ hv_max_functions_eax = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS);
+
pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",
ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,
ms_hyperv.misc_features);
@@ -298,8 +301,7 @@ static void __init ms_hyperv_init_platform(void)
/*
* Extract host information.
*/
- if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
- HYPERV_CPUID_VERSION) {
+ if (hv_max_functions_eax >= HYPERV_CPUID_VERSION) {
hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
@@ -325,9 +327,11 @@ static void __init ms_hyperv_init_platform(void)
ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
}

- if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
+ if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
ms_hyperv.nested_features =
cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
+ pr_info("Hyper-V: Nested features: 0x%x\n",
+ ms_hyperv.nested_features);
}

/*
--
2.25.1