From: Bibo Mao <maobibo@loongson.cn>
To: Huacai Chen <chenhuacai@kernel.org>
Cc: Huacai Chen <chenhuacai@loongson.cn>,
Paolo Bonzini <pbonzini@redhat.com>,
Tianrui Zhao <zhaotianrui@loongson.cn>,
kvm@vger.kernel.org, loongarch@lists.linux.dev,
linux-kernel@vger.kernel.org, Xuerui Wang <kernel@xen0n.name>,
Jiaxun Yang <jiaxun.yang@flygoat.com>,
stable@vger.kernel.org, Aurelien Jarno <aurel32@debian.org>
Subject: Re: [PATCH 1/2] LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust
Date: Mon, 23 Mar 2026 16:08:44 +0800 [thread overview]
Message-ID: <4dfe8b6a-908a-dba3-4b8b-bda84f4cae8a@loongson.cn> (raw)
In-Reply-To: <696c5177-4a89-f0d0-c305-c1581e72aa3d@loongson.cn>
On 2026/3/23 下午3:56, Bibo Mao wrote:
>
>
> On 2026/3/23 下午3:08, Huacai Chen wrote:
>> On Mon, Mar 23, 2026 at 11:16 AM Bibo Mao <maobibo@loongson.cn> wrote:
>>>
>>>
>>>
>>> On 2026/3/22 下午9:53, Huacai Chen wrote:
>>>> kvm_get_vcpu_by_cpuid() takes a cpuid parameter whose type is int, so
>>>> cpuid can be negative. Let kvm_get_vcpu_by_cpuid() return NULL for this
>>>> case so as to make it more robust.
>>>>
>>>> This fix an out-of-bounds access to kvm_arch::phyid_map::phys_map[].
>>>>
>>>> Cc: <stable@vger.kernel.org>
>>>> Fixes: 73516e9da512adc ("LoongArch: KVM: Add vcpu mapping from
>>>> physical cpuid")
>>>> Reported-by: Aurelien Jarno <aurel32@debian.org>
>>>> Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1131431
>>>> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
>>>> ---
>>>> arch/loongarch/kvm/vcpu.c | 3 +++
>>>> 1 file changed, 3 insertions(+)
>>>>
>>>> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
>>>> index 8ffd50a470e6..831f381a8fd1 100644
>>>> --- a/arch/loongarch/kvm/vcpu.c
>>>> +++ b/arch/loongarch/kvm/vcpu.c
>>>> @@ -588,6 +588,9 @@ struct kvm_vcpu *kvm_get_vcpu_by_cpuid(struct
>>>> kvm *kvm, int cpuid)
>>>> {
>>>> struct kvm_phyid_map *map;
>>>>
>>>> + if (cpuid < 0)
>>>> + return NULL;
>>>> +
>>>> if (cpuid >= KVM_MAX_PHYID)
>>>> return NULL;
>>>>
>>>>
>>>
>>> if (cpuid < 0 || cpuid >= KVM_MAX_PHYID)?
>>> however both are OK for me.
>> I use a similar style as kvm_get_vcpu_by_id(). :)
>>
>> But there is another warning which can't be solved by this series (and
>> I doubt whether it can be solved unless revert 01a8e68396a6d51f5b).
>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1131431
>
> what is the kernel config file with bug
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1131431
>
> kvm_eiointc_regs_access() seems has problem, it need convert to void *
> before arithmetic operation. I do not know whether this patch can solve
> this bug.
It is introduced by patch d3e43a1f34ac ("LoongArch: KVM: Use 64-bit
register definition for EIOINTC").
Regards
Bibo Mao
>
> diff --git a/arch/loongarch/kvm/intc/eiointc.c
> b/arch/loongarch/kvm/intc/eiointc.c
> index d2acb4d09e73..71bd67b57338 100644
> --- a/arch/loongarch/kvm/intc/eiointc.c
> +++ b/arch/loongarch/kvm/intc/eiointc.c
> @@ -472,34 +472,34 @@ static int kvm_eiointc_regs_access(struct
> kvm_device *dev,
> switch (addr) {
> case EIOINTC_NODETYPE_START ... EIOINTC_NODETYPE_END:
> offset = (addr - EIOINTC_NODETYPE_START) / 4;
> - p = s->nodetype + offset * 4;
> + p = (void *)s->nodetype + offset * 4;
> break;
> case EIOINTC_IPMAP_START ... EIOINTC_IPMAP_END:
> offset = (addr - EIOINTC_IPMAP_START) / 4;
> - p = &s->ipmap + offset * 4;
> + p = (void *)&s->ipmap + offset * 4;
> break;
> case EIOINTC_ENABLE_START ... EIOINTC_ENABLE_END:
> offset = (addr - EIOINTC_ENABLE_START) / 4;
> - p = s->enable + offset * 4;
> + p = (void *)s->enable + offset * 4;
> break;
> case EIOINTC_BOUNCE_START ... EIOINTC_BOUNCE_END:
> offset = (addr - EIOINTC_BOUNCE_START) / 4;
> - p = s->bounce + offset * 4;
> + p = (void *)s->bounce + offset * 4;
> break;
> case EIOINTC_ISR_START ... EIOINTC_ISR_END:
> offset = (addr - EIOINTC_ISR_START) / 4;
> - p = s->isr + offset * 4;
> + p = (void *)s->isr + offset * 4;
> break;
> case EIOINTC_COREISR_START ... EIOINTC_COREISR_END:
> if (cpu >= s->num_cpu)
> return -EINVAL;
>
> offset = (addr - EIOINTC_COREISR_START) / 4;
> - p = s->coreisr[cpu] + offset * 4;
> + p = (void *)s->coreisr[cpu] + offset * 4;
> break;
> case EIOINTC_COREMAP_START ... EIOINTC_COREMAP_END:
> offset = (addr - EIOINTC_COREMAP_START) / 4;
> - p = s->coremap + offset * 4;
> + p = (void *)s->coremap + offset * 4;
> break;
> default:
> kvm_err("%s: unknown eiointc register, addr = %d\n",
> __func__, addr);
>
>
> Regards
> Bibo Mao
>>
>> Huacai
>>
>>>
>>> Reviewed-by: Bibo Mao <maobibo@loongson.cn>
>>>
next prev parent reply other threads:[~2026-03-23 8:11 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-22 13:53 [PATCH 1/2] LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust Huacai Chen
2026-03-22 13:53 ` [PATCH 2/2] LoongArch: KVM: Handle the case that EIOINTC's coremap is empty Huacai Chen
2026-03-23 3:14 ` Bibo Mao
2026-03-23 3:13 ` [PATCH 1/2] LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust Bibo Mao
2026-03-23 7:08 ` Huacai Chen
2026-03-23 7:56 ` Bibo Mao
2026-03-23 8:08 ` Bibo Mao [this message]
2026-03-23 8:14 ` Huacai Chen
2026-03-23 9:40 ` Bibo Mao
2026-03-23 18:36 ` Aurelien Jarno
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