From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@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
Subject: [PATCH 03/10] KVM: x86: Make kvm_x86_ops' {g,s}et_dr6() hooks optional
Date: Fri, 1 May 2020 21:32:27 -0700 [thread overview]
Message-ID: <20200502043234.12481-4-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200502043234.12481-1-sean.j.christopherson@intel.com>
Make get_dr6() and set_dr6() optional and drop the VMX implementations,
which are for all intents and purposes nops. This avoids a retpoline on
VMX when reading/writing DR6, at minimal cost (~1 uop) to SVM.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 11 -----------
arch/x86/kvm/x86.c | 6 ++++--
2 files changed, 4 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index de18cd386bb1..e157bdc218ea 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5008,15 +5008,6 @@ static int handle_dr(struct kvm_vcpu *vcpu)
return kvm_skip_emulated_instruction(vcpu);
}
-static u64 vmx_get_dr6(struct kvm_vcpu *vcpu)
-{
- return vcpu->arch.dr6;
-}
-
-static void vmx_set_dr6(struct kvm_vcpu *vcpu, unsigned long val)
-{
-}
-
static void vmx_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
{
get_debugreg(vcpu->arch.db[0], 0);
@@ -7799,8 +7790,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
.set_idt = vmx_set_idt,
.get_gdt = vmx_get_gdt,
.set_gdt = vmx_set_gdt,
- .get_dr6 = vmx_get_dr6,
- .set_dr6 = vmx_set_dr6,
.set_dr7 = vmx_set_dr7,
.sync_dirty_debug_regs = vmx_sync_dirty_debug_regs,
.cache_reg = vmx_cache_reg,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8ec356ac1e6e..eccbfcb6a4e5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1069,7 +1069,8 @@ static void kvm_update_dr0123(struct kvm_vcpu *vcpu)
static void kvm_update_dr6(struct kvm_vcpu *vcpu)
{
- if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) &&
+ kvm_x86_ops.set_dr6)
kvm_x86_ops.set_dr6(vcpu, vcpu->arch.dr6);
}
@@ -1148,7 +1149,8 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
case 4:
/* fall through */
case 6:
- if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+ if ((vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) ||
+ !kvm_x86_ops.get_dr6)
*val = vcpu->arch.dr6;
else
*val = kvm_x86_ops.get_dr6(vcpu);
--
2.26.0
next prev parent reply other threads:[~2020-05-02 4:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-02 4:32 [PATCH 00/10] KVM: x86: Misc anti-retpoline optimizations Sean Christopherson
2020-05-02 4:32 ` [PATCH 01/10] KVM: x86: Save L1 TSC offset in 'struct kvm_vcpu_arch' Sean Christopherson
2020-05-02 4:32 ` [PATCH 02/10] KVM: nVMX: Unconditionally validate CR3 during nested transitions Sean Christopherson
2020-05-02 4:32 ` Sean Christopherson [this message]
2020-05-04 13:19 ` [PATCH 03/10] KVM: x86: Make kvm_x86_ops' {g,s}et_dr6() hooks optional Paolo Bonzini
2020-05-02 4:32 ` [PATCH 04/10] KVM: x86: Split guts of kvm_update_dr7() to separate helper Sean Christopherson
2020-05-02 4:32 ` [PATCH 05/10] KVM: nVMX: Avoid retpoline when writing DR7 during nested transitions Sean Christopherson
2020-05-02 4:32 ` [PATCH 06/10] KVM: VMX: Add proper cache tracking for CR4 Sean Christopherson
2020-05-02 4:32 ` [PATCH 07/10] KVM: VMX: Add proper cache tracking for CR0 Sean Christopherson
2020-05-02 4:32 ` [PATCH 08/10] KVM: VMX: Add anti-retpoline accessors for RIP and RSP Sean Christopherson
2020-05-02 4:32 ` [PATCH 09/10] KVM: VMX: Move nested EPT out of kvm_x86_ops.get_tdp_level() hook Sean Christopherson
2020-05-02 4:32 ` [PATCH 10/10] KVM: x86/mmu: Capture TDP level when updating CPUID Sean Christopherson
2020-05-04 13:25 ` [PATCH 00/10] KVM: x86: Misc anti-retpoline optimizations Paolo Bonzini
2020-05-04 15:09 ` Sean Christopherson
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