From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "seanjc@google.com" <seanjc@google.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"oliver.upton@linux.dev" <oliver.upton@linux.dev>,
"Annapurve, Vishal" <vannapurve@google.com>,
"Li, Xiaoyao" <xiaoyao.li@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvmarm@lists.linux.dev" <kvmarm@lists.linux.dev>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"maz@kernel.org" <maz@kernel.org>,
"Hunter, Adrian" <adrian.hunter@intel.com>,
"nik.borisov@suse.com" <nik.borisov@suse.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>
Subject: Re: [PATCH 2/5] KVM: TDX: Exit with MEMORY_FAULT on unexpected pending S-EPT Violation
Date: Tue, 29 Jul 2025 23:13:58 +0000 [thread overview]
Message-ID: <42a1dcc7f8607e526f09c758876e5967eb0e42ae.camel@intel.com> (raw)
In-Reply-To: <aIlUbpQlYqaSO6wr@google.com>
On Tue, 2025-07-29 at 16:08 -0700, Sean Christopherson wrote:
> > If userspace runs the vCPU again then an EPT violation gets triggered again,
> > which again gets kicked out to userspace. The new check will prevent it from
> > getting into the fault handler, right?
>
> Yes? But I'm confused about why you mentioned vm_dead, and why you're calling
> this a "new check". This effectively does two things: drops kvm_vm_dead() and
> switches from EOI => EFAULT. _If_ setting vm_dead was necessary, then we have
> a
> problem.
>
> I assume by "The vm_dead was added" you really mean "forcing an exit to
> userspace",
> and that kvm_vm_dead()+EIO was a somewhat arbitrary way of forcing an exit?
Sorry, yes vm_dead prevents an EPT violation loop but not the KVM_BUG_ON(). The
whole if clause prevents the KVM_BUG_ON(). Your patch prevents the ept violation
loop in a better way.
next prev parent reply other threads:[~2025-07-29 23:14 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-29 19:33 [PATCH 0/5] KVM: Drop vm_dead, pivot on vm_bugged for -EIO Sean Christopherson
2025-07-29 19:33 ` [PATCH 1/5] KVM: Never clear KVM_REQ_VM_DEAD from a vCPU's requests Sean Christopherson
2025-07-29 19:33 ` [PATCH 2/5] KVM: TDX: Exit with MEMORY_FAULT on unexpected pending S-EPT Violation Sean Christopherson
2025-07-29 22:27 ` Edgecombe, Rick P
2025-07-29 22:54 ` Sean Christopherson
2025-07-29 22:58 ` Edgecombe, Rick P
2025-07-29 23:08 ` Sean Christopherson
2025-07-29 23:13 ` Edgecombe, Rick P [this message]
2025-07-30 5:45 ` Yan Zhao
2025-07-30 5:55 ` Yan Zhao
2025-07-30 12:59 ` Edgecombe, Rick P
2025-07-30 2:07 ` Xiaoyao Li
2025-07-30 6:04 ` Yan Zhao
2025-07-29 19:33 ` [PATCH 3/5] KVM: Reject ioctls only if the VM is bugged, not simply marked dead Sean Christopherson
2025-07-30 1:20 ` Chao Gao
2025-07-29 19:33 ` [PATCH 4/5] KVM: selftests: Use for-loop to handle all successful SEV migrations Sean Christopherson
2025-07-29 19:33 ` [PATCH 5/5] KVM: TDX: Add sub-ioctl KVM_TDX_TERMINATE_VM Sean Christopherson
2025-08-01 13:56 ` Adrian Hunter
2025-08-01 16:44 ` Sean Christopherson
2025-08-03 17:41 ` Adrian Hunter
2025-08-06 6:06 ` Chao Gao
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