From: "Jan Beulich" <JBeulich@suse.com>
To: Corneliu ZUZU <czuzu@bitdefender.com>
Cc: Kevin Tian <kevin.tian@intel.com>,
Tamas K Lengyel <tamas@tklengyel.com>,
Razvan Cojocaru <rcojocaru@bitdefender.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
xen-devel@lists.xen.org, Jun Nakajima <jun.nakajima@intel.com>
Subject: Re: [PATCH v3 2/8] x86/vm-event/monitor: relocate code-motion more appropriately
Date: Fri, 08 Jul 2016 01:21:06 -0600 [thread overview]
Message-ID: <577F708202000078000FC79A@prv-mh.provo.novell.com> (raw)
In-Reply-To: <1467820242-13358-1-git-send-email-czuzu@bitdefender.com>
>>> On 06.07.16 at 17:50, <czuzu@bitdefender.com> wrote:
The title of this patch keeps confusing me - which code motion is
being relocated here?
> +void vmx_vm_event_update_cr3_traps(struct domain *d)
Is there anything in this function preventing the parameter to be
const?
> +{
> + struct vcpu *v;
> + struct arch_vmx_struct *avmx;
> + unsigned int cr3_bitmask;
> + bool_t cr3_vmevent, cr3_ldexit;
> +
> + /* domain must be paused */
> + ASSERT(atomic_read(&d->pause_count));
Comment style.
> + /* non-hap domains trap CR3 writes unconditionally */
> + if ( !paging_mode_hap(d) )
> + {
> +#ifndef NDEBUG
> + for_each_vcpu ( d, v )
> + ASSERT(v->arch.hvm_vmx.exec_control & CPU_BASED_CR3_LOAD_EXITING);
> +#endif
> + return;
> + }
> +
> + cr3_bitmask = monitor_ctrlreg_bitmask(VM_EVENT_X86_CR3);
> + cr3_vmevent = !!(d->arch.monitor.write_ctrlreg_enabled & cr3_bitmask);
> +
> + for_each_vcpu ( d, v )
> + {
> + avmx = &v->arch.hvm_vmx;
> + cr3_ldexit = !!(avmx->exec_control & CPU_BASED_CR3_LOAD_EXITING);
> +
> + if ( cr3_vmevent == cr3_ldexit )
> + continue;
> +
> + /*
> + * If CR0.PE=0, CR3 load exiting must remain enabled.
> + * See vmx_update_guest_cr code motion for cr = 0.
> + */
Same as for the title - what code motion is this referring to? In a
code comment you clearly shouldn't be referring to anything the
patch effects, only to its result.
> + if ( cr3_ldexit && !hvm_paging_enabled(v) && !vmx_unrestricted_guest(v) )
> + continue;
The first sentence of the comment should be brought in line with
this condition.
> +static inline void write_ctrlreg_adjust_traps(struct domain *d, uint8_t index)
Unless there is a particular reason for this uint8_t, please convert to
unsigned int.
> +{
> + /* vmx only */
> + ASSERT(cpu_has_vmx);
Comment style (more below). Should perhaps also get "for now" or
some such added.
> +static inline void write_ctrlreg_disable_traps(struct domain *d)
> +{
> + unsigned int old = d->arch.monitor.write_ctrlreg_enabled;
> + d->arch.monitor.write_ctrlreg_enabled = 0;
> +
> + if ( old )
> + {
> + /* vmx only */
> + ASSERT(cpu_has_vmx);
Wouldn't this better move ahead of the if()?
> + /* was CR3 load-exiting enabled due to monitoring? */
> + if ( old & monitor_ctrlreg_bitmask(VM_EVENT_X86_CR3) )
And then this if() alone would suffice.
> @@ -36,11 +63,40 @@ int arch_monitor_init_domain(struct domain *d)
> void arch_monitor_cleanup_domain(struct domain *d)
> {
> xfree(d->arch.monitor.msr_bitmap);
> -
> + write_ctrlreg_disable_traps(d);
> memset(&d->arch.monitor, 0, sizeof(d->arch.monitor));
> memset(&d->monitor, 0, sizeof(d->monitor));
> }
Rather than deleting the blank line, perhaps better to insert another
one after your addition?
Jan
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next prev parent reply other threads:[~2016-07-08 7:21 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-06 15:49 [PATCH v3 0/8] x86/vm-event: Adjustments & fixes Corneliu ZUZU
2016-07-06 15:49 ` [PATCH v3 1/8] x86/vmx_update_guest_cr: minor optimization Corneliu ZUZU
2016-07-08 11:39 ` Corneliu ZUZU
2016-07-08 11:48 ` Jan Beulich
2016-07-08 11:55 ` Corneliu ZUZU
2016-07-08 12:11 ` Jan Beulich
2016-07-08 12:18 ` Ping: " Corneliu ZUZU
2016-07-11 2:37 ` Tian, Kevin
2016-07-06 15:50 ` [PATCH v3 2/8] x86/vm-event/monitor: relocate code-motion more appropriately Corneliu ZUZU
2016-07-08 7:21 ` Jan Beulich [this message]
2016-07-08 10:22 ` Corneliu ZUZU
2016-07-08 10:37 ` Jan Beulich
2016-07-08 11:33 ` Corneliu ZUZU
2016-07-08 11:53 ` Jan Beulich
2016-07-08 11:57 ` Corneliu ZUZU
2016-07-08 15:50 ` Tamas K Lengyel
2016-07-08 17:58 ` Corneliu ZUZU
2016-07-11 2:52 ` Tian, Kevin
2016-07-06 15:51 ` [PATCH v3 3/8] x86/vm-event/monitor: don't compromise monitor_write_data on domain cleanup Corneliu ZUZU
2016-07-08 7:35 ` Jan Beulich
2016-07-08 10:28 ` Corneliu ZUZU
2016-07-08 10:38 ` Jan Beulich
2016-07-06 15:52 ` [PATCH v3 4/8] x86/vm_event/monitor/cr: check for vm-event subscriber on domctl Corneliu ZUZU
2016-07-06 16:01 ` Jan Beulich
2016-07-06 16:15 ` Corneliu ZUZU
2016-07-06 16:20 ` Corneliu ZUZU
2016-07-07 7:30 ` Jan Beulich
2016-07-07 7:53 ` Corneliu ZUZU
2016-07-07 8:18 ` Corneliu ZUZU
2016-07-06 15:53 ` [PATCH v3 5/8] x86/vm_event_resume: surround VM_EVENT_REASON_MOV_TO_MSR w/ CONFIG_X86 Corneliu ZUZU
2016-07-06 15:54 ` [PATCH v3 6/8] x86/vm-event: minor ASSERT fix, add 'unlikely' Corneliu ZUZU
2016-07-07 8:27 ` Jan Beulich
2016-07-07 8:35 ` Corneliu ZUZU
2016-07-07 8:53 ` Jan Beulich
2016-07-07 23:24 ` Tamas K Lengyel
2016-07-06 15:55 ` [PATCH v3 7/8] minor fixes (formatting, comments, unused includes etc.) Corneliu ZUZU
2016-07-08 7:56 ` Jan Beulich
2016-07-08 10:37 ` Corneliu ZUZU
2016-07-06 15:55 ` [PATCH v3 8/8] minor #include change Corneliu ZUZU
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