Commit abc4fc58 authored by Abel Gordon's avatar Abel Gordon Committed by Gleb Natapov
Browse files

KVM: nVMX: Detect shadow-vmcs capability



Add logic required to detect if shadow-vmcs is supported by the
processor. Introduce a new kernel module parameter to specify if L0 should use
shadow vmcs (or not) to run L1.
Signed-off-by: default avatarAbel Gordon <abelg@il.ibm.com>
Reviewed-by: default avatarOrit Wasserman <owasserm@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent 89662e56
......@@ -87,6 +87,8 @@ module_param(fasteoi, bool, S_IRUGO);
static bool __read_mostly enable_apicv = 1;
module_param(enable_apicv, bool, S_IRUGO);
static bool __read_mostly enable_shadow_vmcs = 1;
module_param_named(enable_shadow_vmcs, enable_shadow_vmcs, bool, S_IRUGO);
/*
* If nested=1, nested virtualization is supported, i.e., guests may use
* VMX and be a hypervisor for its own guests. If nested=0, guests may not
......@@ -940,6 +942,18 @@ static inline bool cpu_has_vmx_wbinvd_exit(void)
SECONDARY_EXEC_WBINVD_EXITING;
}
static inline bool cpu_has_vmx_shadow_vmcs(void)
{
u64 vmx_msr;
rdmsrl(MSR_IA32_VMX_MISC, vmx_msr);
/* check if the cpu supports writing r/o exit information fields */
if (!(vmx_msr & MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS))
return false;
return vmcs_config.cpu_based_2nd_exec_ctrl &
SECONDARY_EXEC_SHADOW_VMCS;
}
static inline bool report_flexpriority(void)
{
return flexpriority_enabled;
......@@ -2632,7 +2646,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
SECONDARY_EXEC_RDTSCP |
SECONDARY_EXEC_ENABLE_INVPCID |
SECONDARY_EXEC_APIC_REGISTER_VIRT |
SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY;
SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
SECONDARY_EXEC_SHADOW_VMCS;
if (adjust_vmx_controls(min2, opt2,
MSR_IA32_VMX_PROCBASED_CTLS2,
&_cpu_based_2nd_exec_control) < 0)
......@@ -2833,6 +2848,8 @@ static __init int hardware_setup(void)
if (!cpu_has_vmx_vpid())
enable_vpid = 0;
if (!cpu_has_vmx_shadow_vmcs())
enable_shadow_vmcs = 0;
if (!cpu_has_vmx_ept() ||
!cpu_has_vmx_ept_4levels()) {
......@@ -4077,6 +4094,12 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx)
exec_control &= ~(SECONDARY_EXEC_APIC_REGISTER_VIRT |
SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY);
exec_control &= ~SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE;
/* SECONDARY_EXEC_SHADOW_VMCS is enabled when L1 executes VMPTRLD
(handle_vmptrld).
We can NOT enable shadow_vmcs here because we don't have yet
a current VMCS12
*/
exec_control &= ~SECONDARY_EXEC_SHADOW_VMCS;
return exec_control;
}
......
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