Support access to VMware backdoor requires KVM to intercept #GP
exceptions from guest which introduce slight performance hit.
Therefore, control this support by module parameter.
Note that module parameter is exported as it should be consumed by
kvm_intel & kvm_amd to determine if they should intercept #GP or not.
This commit doesn't change semantics.
It is done as a preparation for future commits.
Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@xxxxxxxxxx>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 3 +++
arch/x86/kvm/x86.c | 4 ++++
arch/x86/kvm/x86.h | 2 ++
3 files changed, 9 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1d1d53f85ddd..0f5e3c8eaf5d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1887,6 +1887,9 @@
kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
Default is 0 (don't ignore, but inject #GP)
+ kvm.enable_vmware_backdoor=[KVM] Support VMware backdoor PV interface.
+ Default is false (don't support).
+
kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
KVM MMU at runtime.
Default is 0 (off)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 18b5ca7a3197..e393c7705807 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -140,6 +140,10 @@
static bool __read_mostly vector_hashing = true;
module_param(vector_hashing, bool, S_IRUGO);
+bool __read_mostly enable_vmware_backdoor = false;
+module_param(enable_vmware_backdoor, bool, S_IRUGO);
+EXPORT_SYMBOL_GPL(enable_vmware_backdoor);
+
#define KVM_NR_SHARED_MSRS 16
struct kvm_shared_msrs_global {
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index b91215d1fd80..18e2e0a91edc 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -242,6 +242,8 @@ bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn,
extern unsigned int lapic_timer_advance_ns;
+extern bool enable_vmware_backdoor;
+
extern struct static_key kvm_no_apic_vcpu;
static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
--
1.9.1
