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 05/10] KVM: nVMX: Avoid retpoline when writing DR7 during nested transitions
Date: Fri, 1 May 2020 21:32:29 -0700 [thread overview]
Message-ID: <20200502043234.12481-6-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200502043234.12481-1-sean.j.christopherson@intel.com>
Add a helper, nested_vmx_set_dr7(), to handle updating DR7 during nested
transitions to avoid bouncing through kvm_update_dr7() and its
potentially retpolined kvm_x86_ops.set_dr7() call. The duplicated code
to adjust the architectural DR7 is minor, and losing the WARN_ON() when
refreshing DR7 from vmcs01 is really no loss at all.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/nested.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 1f2f41e821f9..3b4f1408b4e1 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2116,6 +2116,12 @@ static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu)
ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL);
}
+static void nested_vmx_set_dr7(struct kvm_vcpu *vcpu, unsigned long val)
+{
+ vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
+ vmcs_writel(GUEST_DR7, __kvm_update_dr7(vcpu));
+}
+
static u64 nested_vmx_calc_efer(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
{
if (vmx->nested.nested_run_pending &&
@@ -2487,10 +2493,10 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
if (vmx->nested.nested_run_pending &&
(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS)) {
- kvm_set_dr(vcpu, 7, vmcs12->guest_dr7);
+ nested_vmx_set_dr7(vcpu, vmcs12->guest_dr7);
vmcs_write64(GUEST_IA32_DEBUGCTL, vmcs12->guest_ia32_debugctl);
} else {
- kvm_set_dr(vcpu, 7, vcpu->arch.dr7);
+ nested_vmx_set_dr7(vcpu, vcpu->arch.dr7);
vmcs_write64(GUEST_IA32_DEBUGCTL, vmx->nested.vmcs01_debugctl);
}
if (kvm_mpx_supported() && (!vmx->nested.nested_run_pending ||
@@ -4176,7 +4182,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
};
vmx_set_segment(vcpu, &seg, VCPU_SREG_TR);
- kvm_set_dr(vcpu, 7, 0x400);
+ nested_vmx_set_dr7(vcpu, 0x400);
vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
if (cpu_has_vmx_msr_bitmap())
@@ -4228,9 +4234,9 @@ static void nested_vmx_restore_host_state(struct kvm_vcpu *vcpu)
* nested VMENTER (not worth adding a variable in nested_vmx).
*/
if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
- kvm_set_dr(vcpu, 7, DR7_FIXED_1);
+ nested_vmx_set_dr7(vcpu, DR7_FIXED_1);
else
- WARN_ON(kvm_set_dr(vcpu, 7, vmcs_readl(GUEST_DR7)));
+ nested_vmx_set_dr7(vcpu, vmcs_readl(GUEST_DR7));
}
/*
--
2.26.0
next prev parent reply other threads:[~2020-05-02 4:33 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 ` [PATCH 03/10] KVM: x86: Make kvm_x86_ops' {g,s}et_dr6() hooks optional Sean Christopherson
2020-05-04 13:19 ` 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 ` Sean Christopherson [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200502043234.12481-6-sean.j.christopherson@intel.com \
--to=sean.j.christopherson@intel.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.