From: Xiaoyao Li <xiaoyao.li@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
kvm@vger.kernel.org
Cc: Nadav Amit <namit@cs.technion.ac.il>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
linux-kernel@vger.kernel.org, Xiaoyao Li <xiaoyao.li@intel.com>
Subject: [RFC PATCH 2/3] kvm: x86: Use KVM_DEBUGREG_NEED_RELOAD instead of KVM_DEBUGREG_BP_ENABLED
Date: Thu, 16 Apr 2020 18:15:08 +0800 [thread overview]
Message-ID: <20200416101509.73526-3-xiaoyao.li@intel.com> (raw)
In-Reply-To: <20200416101509.73526-1-xiaoyao.li@intel.com>
Once any #BP enabled in DR7, it will set KVM_DEBUGREG_BP_ENABLED, which
leads to reload DRn before every VM entry even if none of DRn changed.
Drop KVM_DEBUGREG_BP_ENABLED flag and set KVM_DEBUGREG_NEED_RELOAD flag
for the cases that DRn need to be reloaded instead, to avoid unnecessary
DRn reload.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
arch/x86/include/asm/kvm_host.h | 3 +--
arch/x86/kvm/x86.c | 4 ++--
2 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f465c76e6e5a..87e2d020351e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -509,9 +509,8 @@ struct kvm_pmu {
struct kvm_pmu_ops;
enum {
- KVM_DEBUGREG_BP_ENABLED = 1,
+ KVM_DEBUGREG_NEED_RELOAD = 1,
KVM_DEBUGREG_WONT_EXIT = 2,
- KVM_DEBUGREG_NEED_RELOAD = 4,
};
struct kvm_mtrr_range {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cce926658d10..71264df64001 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1086,9 +1086,8 @@ static void kvm_update_dr7(struct kvm_vcpu *vcpu)
else
dr7 = vcpu->arch.dr7;
kvm_x86_ops.set_dr7(vcpu, dr7);
- vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_BP_ENABLED;
if (dr7 & DR7_BP_EN_MASK)
- vcpu->arch.switch_db_regs |= KVM_DEBUGREG_BP_ENABLED;
+ vcpu->arch.switch_db_regs |= KVM_DEBUGREG_NEED_RELOAD;
}
static u64 kvm_dr6_fixed(struct kvm_vcpu *vcpu)
@@ -1128,6 +1127,7 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
break;
}
+ vcpu->arch.switch_db_regs |= KVM_DEBUGREG_NEED_RELOAD;
return 0;
}
--
2.20.1
next prev parent reply other threads:[~2020-04-16 10:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-16 10:15 [RFC PATCH 0/3] kvm: x86: Cleanup and optimazation of switch_db_regs Xiaoyao Li
2020-04-16 10:15 ` [RFC PATCH 1/3] kvm: x86: Rename KVM_DEBUGREG_RELOAD to KVM_DEBUGREG_NEED_RELOAD Xiaoyao Li
2020-04-23 19:09 ` Sean Christopherson
2020-04-24 13:28 ` Xiaoyao Li
2020-04-24 20:21 ` Peter Xu
2020-04-24 20:29 ` Sean Christopherson
2020-04-24 20:59 ` Peter Xu
2020-04-25 7:48 ` Paolo Bonzini
2020-04-27 14:37 ` Peter Xu
2020-04-27 16:06 ` Xiaoyao Li
2020-04-25 8:07 ` Paolo Bonzini
2020-04-25 16:54 ` Nadav Amit
2020-04-25 19:16 ` Paolo Bonzini
2020-04-16 10:15 ` Xiaoyao Li [this message]
2020-04-23 19:29 ` [RFC PATCH 2/3] kvm: x86: Use KVM_DEBUGREG_NEED_RELOAD instead of KVM_DEBUGREG_BP_ENABLED Sean Christopherson
2020-04-24 13:21 ` Xiaoyao Li
2020-04-16 10:15 ` [RFC PATCH 3/3] kvm: x86: skip DRn reload if previous VM exit is DR access VM exit Xiaoyao Li
2020-04-23 19:31 ` Sean Christopherson
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