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

Paolo Bonzini
2021-07-26T22:04:02Z

On 26/07/21 23:17, Sudip Mukherjee wrote:
> Hi Greg,
>
> On Mon, Jul 26, 2021 at 4:58 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
>>
>> From: Paolo Bonzini <pbonzini@redhat.com>
>>
>> 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).

Paolo