From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Reto Buerki <reet@codelabs.ch>,
Liran Alon <liran.alon@oracle.com>
Subject: [PATCH v2 4/8] KVM: VMX: Optimize vmx_set_rflags() for unrestricted guest
Date: Fri, 27 Sep 2019 14:45:19 -0700 [thread overview]
Message-ID: <20190927214523.3376-5-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190927214523.3376-1-sean.j.christopherson@intel.com>
Rework vmx_set_rflags() to avoid the extra code need to handle emulation
of real mode and invalid state when unrestricted guest is disabled. The
primary reason for doing so is to avoid the call to vmx_get_rflags(),
which will incur a VMREAD when RFLAGS is not already available. When
running nested VMs, the majority of calls to vmx_set_rflags() will occur
without an associated vmx_get_rflags(), i.e. when stuffing GUEST_RFLAGS
during transitions between vmcs01 and vmcs02.
Note, vmx_get_rflags() guarantees RFLAGS is marked available.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 83fe8b02b732..814d3e6d0264 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1426,18 +1426,26 @@ unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu)
void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- unsigned long old_rflags = vmx_get_rflags(vcpu);
+ unsigned long old_rflags;
- __set_bit(VCPU_EXREG_RFLAGS, (ulong *)&vcpu->arch.regs_avail);
- vmx->rflags = rflags;
- if (vmx->rmode.vm86_active) {
- vmx->rmode.save_rflags = rflags;
- rflags |= X86_EFLAGS_IOPL | X86_EFLAGS_VM;
+ if (enable_unrestricted_guest) {
+ __set_bit(VCPU_EXREG_RFLAGS, (ulong *)&vcpu->arch.regs_avail);
+
+ vmx->rflags = rflags;
+ vmcs_writel(GUEST_RFLAGS, rflags);
+ } else {
+ old_rflags = vmx_get_rflags(vcpu);
+
+ vmx->rflags = rflags;
+ if (vmx->rmode.vm86_active) {
+ vmx->rmode.save_rflags = rflags;
+ rflags |= X86_EFLAGS_IOPL | X86_EFLAGS_VM;
+ }
+ vmcs_writel(GUEST_RFLAGS, rflags);
+
+ if ((old_rflags ^ vmx->rflags) & X86_EFLAGS_VM)
+ vmx->emulation_required = emulation_required(vcpu);
}
- vmcs_writel(GUEST_RFLAGS, rflags);
-
- if ((old_rflags ^ vmx->rflags) & X86_EFLAGS_VM)
- vmx->emulation_required = emulation_required(vcpu);
}
u32 vmx_get_interrupt_shadow(struct kvm_vcpu *vcpu)
--
2.22.0
next prev parent reply other threads:[~2019-09-27 21:45 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-27 21:45 [PATCH v2 0/8] KVM: x86: nVMX GUEST_CR3 bug fix, and then some Sean Christopherson
2019-09-27 21:45 ` [PATCH v2 1/8] KVM: nVMX: Always write vmcs02.GUEST_CR3 during nested VM-Enter Sean Christopherson
2019-09-27 23:37 ` Jim Mattson
2019-09-27 21:45 ` [PATCH v2 2/8] KVM: VMX: Skip GUEST_CR3 VMREAD+VMWRITE if the VMCS is up-to-date Sean Christopherson
2019-09-27 21:45 ` [PATCH v2 3/8] KVM: VMX: Consolidate to_vmx() usage in RFLAGS accessors Sean Christopherson
2019-09-30 8:48 ` Vitaly Kuznetsov
2019-09-27 21:45 ` Sean Christopherson [this message]
2019-09-30 8:57 ` [PATCH v2 4/8] KVM: VMX: Optimize vmx_set_rflags() for unrestricted guest Vitaly Kuznetsov
2019-09-30 15:19 ` Sean Christopherson
2019-09-30 15:55 ` Vitaly Kuznetsov
2019-10-09 10:40 ` Paolo Bonzini
2019-10-09 16:38 ` Sean Christopherson
2019-10-09 20:59 ` Paolo Bonzini
2019-10-09 21:30 ` Sean Christopherson
2019-09-27 21:45 ` [PATCH v2 5/8] KVM: x86: Add WARNs to detect out-of-bounds register indices Sean Christopherson
2019-09-30 9:19 ` Vitaly Kuznetsov
2019-10-09 10:50 ` Paolo Bonzini
2019-10-09 16:36 ` Sean Christopherson
2019-09-27 21:45 ` [PATCH v2 6/8] KVM: x86: Fold 'enum kvm_ex_reg' definitions into 'enum kvm_reg' Sean Christopherson
2019-09-30 9:25 ` Vitaly Kuznetsov
2019-10-09 10:52 ` Paolo Bonzini
2019-10-09 11:27 ` Vitaly Kuznetsov
2019-09-27 21:45 ` [PATCH v2 7/8] KVM: x86: Add helpers to test/mark reg availability and dirtiness Sean Christopherson
2019-09-30 9:32 ` Vitaly Kuznetsov
2019-10-09 11:00 ` Paolo Bonzini
2019-09-27 21:45 ` [PATCH v2 8/8] KVM: x86: Fold decache_cr3() into cache_reg() Sean Christopherson
2019-09-30 10:58 ` Vitaly Kuznetsov
2019-09-30 15:04 ` Sean Christopherson
2019-09-30 15:27 ` Vitaly Kuznetsov
2019-09-30 15:33 ` Sean Christopherson
2019-10-09 11:03 ` Paolo Bonzini
2019-09-30 10:42 ` [PATCH v2 0/8] KVM: x86: nVMX GUEST_CR3 bug fix, and then some Reto Buerki
2019-10-29 15:03 ` Martin Lucina
2019-10-30 9:09 ` Sean Christopherson
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