From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>, Peter Xu <peterx@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Ben Gardon <bgardon@google.com>,
David Matlack <dmatlack@google.com>,
Andrew Jones <drjones@redhat.com>
Subject: Re: [PATCH] kvm: selftests: Fix cut-off of addr_gva2gpa lookup
Date: Thu, 14 Apr 2022 16:14:22 +0200 [thread overview]
Message-ID: <bf15209d-2c50-9957-af24-c4f428f213b1@redhat.com> (raw)
In-Reply-To: <Ylgn/Jw+FMIFqqc0@google.com>
On 4/14/22 15:56, Sean Christopherson wrote:
>> - return (pte[index[0]].pfn * vm->page_size) + (gva & 0xfffu);
>> + return ((vm_paddr_t)pte[index[0]].pfn * vm->page_size) + (gva & 0xfffu);
> This is but one of many paths that can get burned by pfn being 40 bits. The
> most backport friendly fix is probably to add a pfn=>gpa helper and use that to
> place the myriad "pfn * vm->page_size" instances.
>
> For a true long term solution, my vote is to do away with the bit field struct
> and use #define'd masks and whatnot.
Yes, bitfields larger than 32 bits are a mess.
Paolo
next prev parent reply other threads:[~2022-04-14 15:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 1:07 [PATCH] kvm: selftests: Fix cut-off of addr_gva2gpa lookup Peter Xu
2022-04-14 1:19 ` Peter Xu
2022-04-14 13:56 ` Sean Christopherson
2022-04-14 14:14 ` Paolo Bonzini [this message]
2022-04-14 21:34 ` Peter Xu
2022-04-14 22:01 ` Jim Mattson
2022-04-15 0:30 ` Peter Xu
2022-04-14 15:05 ` Peter Xu
2022-04-14 15:20 ` Paolo Bonzini
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