From: Paolo Bonzini <pbonzini@redhat.com>
To: Xiaoyao Li <xiaoyao.li@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sean Christopherson <sean.j.christopherson@intel.com>
Cc: x86@kernel.org, "Kenneth R . Crudup" <kenny@panix.com>,
Fenghua Yu <fenghua.yu@intel.com>, Nadav Amit <namit@vmware.com>,
Thomas Hellstrom <thellstrom@vmware.com>,
Tony Luck <tony.luck@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Jessica Yu <jeyu@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] x86/split_lock: Refactor and export handle_user_split_lock() for KVM
Date: Fri, 10 Apr 2020 12:21:36 +0200 [thread overview]
Message-ID: <283c549a-423f-a85e-c208-8a80d682ef77@redhat.com> (raw)
In-Reply-To: <716f5824-8d47-24cc-4935-c2dd32ed4629@intel.com>
On 10/04/20 06:39, Xiaoyao Li wrote:
>
> +static bool guest_handles_ac(struct kvm_vcpu *vcpu)
> +{
> + /*
> + * If guest has alignment checking enabled in CR0 and activated in
> + * eflags, then the #AC originated from CPL3 and the guest is able
> + * to handle it. It does not matter whether this is a regular or
> + * a split lock operation induced #AC.
> + */
> + if (vmx_get_cpl(vcpu) == 3 && kvm_read_cr0_bits(vcpu, X86_CR0_AM) &&
> + kvm_get_rflags(vcpu) & X86_EFLAGS_AC)
> + return true;
> +
> + /* Add guest SLD handling checks here once it's supported */
> + return false;
> +}
> +
> static int handle_exception_nmi(struct kvm_vcpu *vcpu)
> {
> struct vcpu_vmx *vmx = to_vmx(vcpu);
> @@ -4630,6 +4647,7 @@ static int handle_exception_nmi(struct k
> u32 intr_info, ex_no, error_code;
> unsigned long cr2, rip, dr6;
> u32 vect_info;
> + int err;
> vect_info = vmx->idt_vectoring_info;
> intr_info = vmx->exit_intr_info;
> @@ -4688,9 +4706,6 @@ static int handle_exception_nmi(struct k
> return handle_rmode_exception(vcpu, ex_no, error_code);
> switch (ex_no) {
> - case AC_VECTOR:
> - kvm_queue_exception_e(vcpu, AC_VECTOR, error_code);
> - return 1;
> case DB_VECTOR:
> dr6 = vmcs_readl(EXIT_QUALIFICATION);
> if (!(vcpu->guest_debug &
> @@ -4719,6 +4734,29 @@ static int handle_exception_nmi(struct k
> kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip;
> kvm_run->debug.arch.exception = ex_no;
> break;
> + case AC_VECTOR:
> + if (guest_handles_ac(vcpu)) {
> + kvm_queue_exception_e(vcpu, AC_VECTOR, error_code);
> + return 1;
> + }
> + /*
> + * Handle #AC caused by split lock detection. If the host
> + * mode is sld_warn, then it warns, marks current with
> + * TIF_SLD and disables split lock detection. So the guest
> + * can just continue.
> + *
> + * If the host mode is fatal, the handling code warned. Let
> + * qemu kill itself.
> + *
> + * If the host mode is off, then this #AC is bonkers and
> + * something is badly wrong. Let it fail as well.
> + */
> + err = handle_ac_split_lock(kvm_rip_read(vcpu));
> + if (!err)
> + return 1;
> + /* Propagate the error type to user space */
> + error_code = err == -EFAULT ? 0x100 : 0x200;
> + fallthrough;
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
next prev parent reply other threads:[~2020-04-10 10:22 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-02 12:32 [patch 0/2] x86: Prevent Split-Lock-Detection wreckage on VMX hypervisors Thomas Gleixner
2020-04-02 12:32 ` [patch 1/2] x86,module: Detect VMX modules and disable Split-Lock-Detect Thomas Gleixner
2020-04-02 15:23 ` [patch v2 " Peter Zijlstra
2020-04-02 16:20 ` Xiaoyao Li
2020-04-02 16:25 ` Peter Zijlstra
2020-04-02 16:39 ` Nadav Amit
2020-04-02 16:41 ` Xiaoyao Li
2020-04-02 17:34 ` Thomas Gleixner
2020-04-02 17:51 ` Sean Christopherson
2020-04-02 18:51 ` Peter Zijlstra
2020-04-02 20:23 ` Sean Christopherson
2020-04-02 21:04 ` Thomas Gleixner
2020-04-02 21:16 ` Sean Christopherson
2020-04-03 8:09 ` David Laight
2020-04-03 14:33 ` Peter Zijlstra
2020-04-02 23:42 ` [patch " Rasmus Villemoes
2020-04-03 14:35 ` Jessica Yu
2020-04-03 15:21 ` Peter Zijlstra
2020-04-03 16:01 ` Sean Christopherson
2020-04-03 16:12 ` Peter Zijlstra
2020-04-03 16:16 ` David Laight
2020-04-03 16:39 ` Peter Zijlstra
2020-04-03 16:25 ` Sean Christopherson
2020-04-03 16:40 ` Peter Zijlstra
2020-04-03 16:48 ` Nadav Amit
2020-04-03 17:21 ` Sean Christopherson
2020-04-03 18:53 ` Thomas Gleixner
2020-04-03 20:58 ` Andy Lutomirski
2020-04-03 21:49 ` Thomas Gleixner
2020-04-03 11:29 ` kbuild test robot
2020-04-03 14:43 ` kbuild test robot
2020-04-03 16:36 ` Sean Christopherson
2020-04-03 16:41 ` Peter Zijlstra
2020-04-03 18:35 ` Jessica Yu
2020-04-06 12:23 ` Christoph Hellwig
2020-04-06 14:40 ` Peter Zijlstra
2020-04-06 15:18 ` Christoph Hellwig
2020-04-06 15:22 ` Peter Zijlstra
2020-04-06 18:27 ` Steven Rostedt
2020-04-02 12:33 ` [patch 2/2] x86/kvm/vmx: Prevent split lock detection induced #AC wreckage Thomas Gleixner
2020-04-02 15:30 ` Sean Christopherson
2020-04-02 15:44 ` Nadav Amit
2020-04-02 16:04 ` Sean Christopherson
2020-04-02 16:56 ` Thomas Gleixner
2020-04-02 15:55 ` [PATCH 0/3] x86: KVM: VMX: Add basic split-lock #AC handling Sean Christopherson
2020-04-02 15:55 ` [PATCH 1/3] KVM: x86: Emulate split-lock access as a write in emulator Sean Christopherson
2020-04-02 15:55 ` [PATCH 2/3] x86/split_lock: Refactor and export handle_user_split_lock() for KVM Sean Christopherson
2020-04-02 17:01 ` Thomas Gleixner
2020-04-02 17:19 ` Sean Christopherson
2020-04-02 19:06 ` Thomas Gleixner
2020-04-10 4:39 ` Xiaoyao Li
2020-04-10 10:21 ` Paolo Bonzini [this message]
2020-04-02 15:55 ` [PATCH 3/3] KVM: VMX: Extend VMX's #AC interceptor to handle split lock #AC in guest Sean Christopherson
2020-04-02 17:19 ` Thomas Gleixner
2020-04-02 17:40 ` Sean Christopherson
2020-04-02 20:07 ` Thomas Gleixner
2020-04-02 20:36 ` Andy Lutomirski
2020-04-02 20:48 ` Peter Zijlstra
2020-04-02 20:51 ` Sean Christopherson
2020-04-02 22:27 ` Thomas Gleixner
2020-04-02 22:40 ` Nadav Amit
2020-04-02 23:03 ` Thomas Gleixner
2020-04-02 23:08 ` Steven Rostedt
2020-04-02 23:16 ` Kenneth R. Crudup
2020-04-02 23:18 ` Jim Mattson
2020-04-03 12:16 ` Thomas Gleixner
2020-04-10 10:23 ` [PATCH 0/3] x86: KVM: VMX: Add basic split-lock #AC handling Paolo Bonzini
2020-04-10 11:14 ` Thomas Gleixner
2020-04-02 13:43 ` [patch 0/2] x86: Prevent Split-Lock-Detection wreckage on VMX hypervisors Kenneth R. Crudup
2020-04-02 14:32 ` Peter Zijlstra
2020-04-02 14:41 ` Kenneth R. Crudup
2020-04-02 14:46 ` Peter Zijlstra
2020-04-02 14:53 ` Kenneth R. Crudup
2020-04-02 14:37 ` Thomas Gleixner
2020-04-02 14:47 ` Nadav Amit
2020-04-02 15:11 ` Peter Zijlstra
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