MIME-Version: 1.0
References: <20211117060241.611391-1-anup.patel@wdc.com>
In-Reply-To: <20211117060241.611391-1-anup.patel@wdc.com>
From:   Atish Patra <atishp@atishpatra.org>
Date:   Wed, 17 Nov 2021 23:53:20 -0800
Message-ID: <CAOnJCU+KZn2JnZg-FZcJ7PXRpGo5SyOmdUYFeJgBenPO9xxE1w@mail.gmail.com>
Subject: Re: [PATCH] RISC-V: KVM: Fix incorrect KVM_MAX_VCPUS value
To:     Anup Patel <anup.patel@wdc.com>
Cc:     Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Anup Patel <anup@brainfault.org>,
        kvm-riscv@lists.infradead.org, kvm@vger.kernel.org,
        linux-riscv <linux-riscv@lists.infradead.org>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Nov 16, 2021 at 10:03 PM Anup Patel <anup.patel@wdc.com> wrote:
>
> The KVM_MAX_VCPUS value is supposed to be aligned with number of
> VMID bits in the hgatp CSR but the current KVM_MAX_VCPUS value
> is aligned with number of ASID bits in the satp CSR.
>
> Fixes: 99cdc6c18c2d ("RISC-V: Add initial skeletal KVM support")
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> ---
>  arch/riscv/include/asm/kvm_host.h | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> index 25ba21f98504..2639b9ee48f9 100644
> --- a/arch/riscv/include/asm/kvm_host.h
> +++ b/arch/riscv/include/asm/kvm_host.h
> @@ -12,14 +12,12 @@
>  #include <linux/types.h>
>  #include <linux/kvm.h>
>  #include <linux/kvm_types.h>
> +#include <asm/csr.h>
>  #include <asm/kvm_vcpu_fp.h>
>  #include <asm/kvm_vcpu_timer.h>
>
> -#ifdef CONFIG_64BIT
> -#define KVM_MAX_VCPUS                  (1U << 16)
> -#else
> -#define KVM_MAX_VCPUS                  (1U << 9)
> -#endif
> +#define KVM_MAX_VCPUS                  \
> +       ((HGATP_VMID_MASK >> HGATP_VMID_SHIFT) + 1)
>
>  #define KVM_HALT_POLL_NS_DEFAULT       500000
>
> --
> 2.25.1
>


Reviewed-by: Atish Patra <atishp@rivosinc.com>

-- 
Regards,
Atish