From: Ralf Baechle <ralf@linux-mips.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "James Hogan" <james.hogan@imgtec.com>,
"Paul Burton" <paul.burton@imgtec.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
linux-mips@linux-mips.org, kvm@vger.kernel.org
Subject: Re: [PATCH 1/7] MIPS: KVM/locore.S: Don't preserve host ASID around vcpu_run
Date: Mon, 9 May 2016 17:30:44 +0200 [thread overview]
Message-ID: <20160509153044.GD28818@linux-mips.org> (raw)
In-Reply-To: <57309D29.6010903@redhat.com>
On Mon, May 09, 2016 at 04:22:33PM +0200, Paolo Bonzini wrote:
> On 06/05/2016 15:36, James Hogan wrote:
> > - It is actually redundant, since the host ASID will be restored
> > correctly by kvm_arch_vcpu_put(), which is called almost immediately
> > after kvm_arch_vcpu_ioctl_run() returns.
>
> What happens if the guest does a rogue access to the area where the host
> kernel resides? Would that cause a wrong entry in the TLB?
The kernel and lowmem reside in KSEG0/XKPYS which are "unmapped segments".
Unmapped means, the TLB isn't accessed at all nor does the ASID matter
in the address translation process in one of these unmapped segments.
Ralf
next prev parent reply other threads:[~2016-05-09 15:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-06 13:36 [PATCH 0/7] MIPS: Add extended ASID support James Hogan
2016-05-06 13:36 ` [PATCH 1/7] MIPS: KVM/locore.S: Don't preserve host ASID around vcpu_run James Hogan
2016-05-09 14:22 ` Paolo Bonzini
2016-05-09 15:30 ` Ralf Baechle [this message]
2016-05-09 19:42 ` James Hogan
2016-05-06 13:36 ` [PATCH 2/7] MIPS: Add & use CP0_EntryHi ASID definitions James Hogan
2016-05-06 13:36 ` [PATCH 3/7] MIPS: KVM: Abstract guest ASID mask James Hogan
2016-05-06 13:36 ` [PATCH 4/7] MIPS: KVM/locore.S: Only preserve callee saved registers James Hogan
2016-05-06 13:36 ` [PATCH 5/7] MIPS: KVM/locore.S: Relax noat James Hogan
2016-05-06 13:36 ` [PATCH 6/7] MIPS: Retrieve ASID masks using function accepting struct cpuinfo_mips James Hogan
2016-05-06 13:36 ` [PATCH 7/7] MIPS: Support extended ASIDs James Hogan
2016-05-09 13:23 ` [PATCH 0/7] MIPS: Add extended ASID support Ralf Baechle
2016-05-09 17:01 ` Maciej W. Rozycki
2016-05-09 19:04 ` James Hogan
2016-05-09 19:56 ` Maciej W. Rozycki
2016-05-09 19:59 ` James Hogan
2016-05-10 7:34 ` Ralf Baechle
2016-05-10 8:55 ` Maciej W. Rozycki
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