[PATCH v2] KVM: nVMX: expose INS/OUTS information support

From: Jan Dakinevich <jan.dakinevich@gmail.com>
To: kvm@vger.kernel.org
Cc: pbonzini@redhat.com, rkrcmar@redhat.com,
	linux-kernel@vger.kernel.org, ynorov@caviumnetworks.com,
	Jan Dakinevich <jan.dakinevich@gmail.com>
Subject: [PATCH v2] KVM: nVMX: expose INS/OUTS information support
Date: Mon,  5 Sep 2016 17:47:59 +0300	[thread overview]
Message-ID: <1473086879-27087-1-git-send-email-jan.dakinevich@gmail.com> (raw)
In-Reply-To: <2bb16b3e-90c2-0d6d-cdf3-81addb170a7e@redhat.com>

Expose the feature to L1 hypervisor if host CPU supports it, since
certain hypervisors requires it for own purposes.

According to Intel SDM A.1, if CPU supports the feature,
VMX_INSTRUCTION_INFO field of VMCS will contain detailed information
about INS/OUTS instructions handling. This field is already copied to
VMCS12 for L1 hypervisor (see prepare_vmcs12 routine) independently of
feature presence.

Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
---
v1:
 * don't copy to basic_cap bits, which are already copied to size field
 * fix commit message

 arch/x86/kvm/vmx.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a4bb2bd..10f9fb5 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -939,6 +939,7 @@ static DEFINE_SPINLOCK(vmx_vpid_lock);
 static struct vmcs_config {
 	int size;
 	int order;
+	u32 basic_cap;
 	u32 revision_id;
 	u32 pin_based_exec_ctrl;
 	u32 cpu_based_exec_ctrl;
@@ -1215,6 +1216,11 @@ static inline bool cpu_has_vmx_ple(void)
 		SECONDARY_EXEC_PAUSE_LOOP_EXITING;
 }
 
+static inline bool cpu_has_vmx_basic_inout(void)
+{
+	return	(((u64)vmcs_config.basic_cap << 32) & VMX_BASIC_INOUT);
+}
+
 static inline bool cpu_need_virtualize_apic_accesses(struct kvm_vcpu *vcpu)
 {
 	return flexpriority_enabled && lapic_in_kernel(vcpu);
@@ -2877,6 +2883,8 @@ static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
 		*pdata = VMCS12_REVISION | VMX_BASIC_TRUE_CTLS |
 			   ((u64)VMCS12_SIZE << VMX_BASIC_VMCS_SIZE_SHIFT) |
 			   (VMX_BASIC_MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
+		if (cpu_has_vmx_basic_inout())
+			*pdata |= VMX_BASIC_INOUT;
 		break;
 	case MSR_IA32_VMX_TRUE_PINBASED_CTLS:
 	case MSR_IA32_VMX_PINBASED_CTLS:
@@ -3458,6 +3466,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 
 	vmcs_conf->size = vmx_msr_high & 0x1fff;
 	vmcs_conf->order = get_order(vmcs_config.size);
+	vmcs_conf->basic_cap = vmx_msr_high & ~0x1fff;
 	vmcs_conf->revision_id = vmx_msr_low;
 
 	vmcs_conf->pin_based_exec_ctrl = _pin_based_exec_control;
-- 
1.9.1
