From: Paolo Bonzini <pbonzini@redhat.com>
To: David Laight <David.Laight@ACULAB.COM>,
'Jim Mattson' <jmattson@google.com>
Cc: 'LKML' <linux-kernel@vger.kernel.org>,
'kvm list' <kvm@vger.kernel.org>,
'Sean Christopherson' <sean.j.christopherson@intel.com>,
'Joerg Roedel' <joro@8bytes.org>,
"'everdox@gmail.com'" <everdox@gmail.com>
Subject: Re: [PATCH] KVM: x86: handle wrap around 32-bit address space
Date: Thu, 30 Apr 2020 14:45:19 +0200 [thread overview]
Message-ID: <2f471fbc-99fb-1a85-8f9f-c276c897f518@redhat.com> (raw)
In-Reply-To: <91c76eb0edcd4f1a9d5bc541d35f8ade@AcuMS.aculab.com>
On 29/04/20 10:56, David Laight wrote:
>>>> + if (unlikely(((rip ^ orig_rip) >> 31) == 3) && !is_64_bit_mode(vcpu))
>> Isn't the more obvious:
>> if (((rip ^ orig_rip) & 1ull << 32) ...
>> equivalent?
This one would not (it would also detect carry on high memory addresses,
not just 0x7fffffff to 0x80000000)...
> Actually not even being clever, how about:
> if (orig_rip < (1ull << 32) && unlikely(rip >= (1ull << 32)) && ...
... but yes this one would be equivalent.
Paolo
next prev parent reply other threads:[~2020-04-30 12:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-27 16:59 [PATCH] KVM: x86: handle wrap around 32-bit address space Paolo Bonzini
2020-04-28 0:28 ` Jim Mattson
2020-04-28 0:33 ` Sean Christopherson
2020-04-29 8:50 ` David Laight
2020-04-29 8:56 ` David Laight
2020-04-30 12:45 ` Paolo Bonzini [this message]
2020-04-30 13:18 ` David Laight
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