Re: [PATCH 4.19 111/120] KVM: do not assume PTE is writable after follow_pfn

[Ovidiu Panait]

Hi,

On 7/27/21 1:02 AM, Paolo Bonzini wrote:

> [Please note: This e-mail is from an EXTERNAL e-mail address]
>
> On 26/07/21 23:17, Sudip Mukherjee wrote:
> > Hi Greg,
> >
> > On Mon, Jul 26, 2021 at 4:58 PM Greg Kroah-Hartman
> > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > > From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > >
> > > commit bd2fae8da794b55bf2ac02632da3a151b10e664c upstream.
> >
> > The build of mips malta_kvm_defconfig fails with the error:
> > In file included from arch/mips/kvm/../../../virt/kvm/kvm_main.c:21:
> > arch/mips/kvm/../../../virt/kvm/kvm_main.c: In function 
> > 'hva_to_pfn_remapped':
> > ./include/linux/kvm_host.h:70:33: error: conversion from 'long long
> > unsigned int' to 'long unsigned int' changes value from
> > '9218868437227405314' to '2' [-Werror=overflow]
> >     70 | #define KVM_PFN_ERR_RO_FAULT    (KVM_PFN_ERR_MASK + 2)
> >        |                                 ^
> > arch/mips/kvm/../../../virt/kvm/kvm_main.c:1530:23: note: in expansion
> > of macro 'KVM_PFN_ERR_RO_FAULT'
> >   1530 |                 pfn = KVM_PFN_ERR_RO_FAULT;
> >
> > It built fine after reverting this patch.
> > gcc version 11.1.1 20210723
>
> I'll resend a version that works tomorrow (including the second patch
> too, which depends on this one for context).
The following upstream commit needed to be backported as well:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a9545779ee9e9e103648f6f2552e73cfe808d0f4


I have sent v2 for this patchset.


Thanks!

Ovidiu


> Paolo