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Message-ID: <CAAhSdy3q3tNUqSxnFy2tdmXOLJZjt4rMAZirZh88-0BXT7-X1g@mail.gmail.com>
Date: Sun, 26 Jul 2020 18:27:16 +0530
From: Anup Patel <anup@...infault.org>
To: Yifei Jiang <jiangyifei@...wei.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Anup Patel <anup.patel@....com>,
Atish Patra <atish.patra@....com>,
KVM General <kvm@...r.kernel.org>,
kvm-riscv@...ts.infradead.org,
linux-riscv <linux-riscv@...ts.infradead.org>,
"linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>,
"Zhangxiaofeng (F)" <victor.zhangxiaofeng@...wei.com>,
wu.wubin@...wei.com,
Zhanghailiang <zhang.zhanghailiang@...wei.com>,
"dengkai (A)" <dengkai1@...wei.com>, limingwang@...wei.com
Subject: Re: [RFC 2/2] RISC-V: KVM: read\write kernel mmio device support
On Fri, Jul 24, 2020 at 2:25 PM Yifei Jiang <jiangyifei@...wei.com> wrote:
>
> Signed-off-by: Yifei Jiang <jiangyifei@...wei.com>
> Signed-off-by: Mingwang Li <limingwang@...wei.com>
> ---
> arch/riscv/kvm/vcpu_exit.c | 38 ++++++++++++++++++++++++++++++++------
> 1 file changed, 32 insertions(+), 6 deletions(-)
>
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index e97ba96cb0ae..448f11179fa8 100644
> --- a/arch/riscv/kvm/vcpu_exit.c
> +++ b/arch/riscv/kvm/vcpu_exit.c
> @@ -191,6 +191,8 @@ static int virtual_inst_fault(struct kvm_vcpu *vcpu, struct kvm_run *run,
> static int emulate_load(struct kvm_vcpu *vcpu, struct kvm_run *run,
> unsigned long fault_addr, unsigned long htinst)
> {
> + int ret;
> + u8 data_buf[8];
> unsigned long insn;
> int shift = 0, len = 0;
> struct kvm_cpu_trap utrap = { 0 };
> @@ -272,19 +274,32 @@ static int emulate_load(struct kvm_vcpu *vcpu, struct kvm_run *run,
> vcpu->arch.mmio_decode.len = len;
> vcpu->arch.mmio_decode.return_handled = 0;
>
> - /* Exit to userspace for MMIO emulation */
> - vcpu->stat.mmio_exit_user++;
> - run->exit_reason = KVM_EXIT_MMIO;
> + ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_addr, len,
> + data_buf);
> +
Move "ret = kvm_io_bus_read()" just before "if (!ret)".
> run->mmio.is_write = false;
> run->mmio.phys_addr = fault_addr;
> run->mmio.len = len;
>
> + if (!ret) {
> + /* We handled the access successfully in the kernel. */
> + memcpy(run->mmio.data, data_buf, len);
> + vcpu->stat.mmio_exit_kernel++;
> + kvm_riscv_vcpu_mmio_return(vcpu, run);
> + return 1;
> + }
> +
> + /* Exit to userspace for MMIO emulation */
> + vcpu->stat.mmio_exit_user++;
> + run->exit_reason = KVM_EXIT_MMIO;
> +
> return 0;
> }
>
> static int emulate_store(struct kvm_vcpu *vcpu, struct kvm_run *run,
> unsigned long fault_addr, unsigned long htinst)
> {
> + int ret;
> u8 data8;
> u16 data16;
> u32 data32;
> @@ -378,13 +393,24 @@ static int emulate_store(struct kvm_vcpu *vcpu, struct kvm_run *run,
> return -ENOTSUPP;
> };
>
> - /* Exit to userspace for MMIO emulation */
> - vcpu->stat.mmio_exit_user++;
> - run->exit_reason = KVM_EXIT_MMIO;
> + ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_addr, len,
> + run->mmio.data);
> +
Same as above.
Move "ret = kvm_io_bus_write()" just before "if (!ret) {"
> run->mmio.is_write = true;
> run->mmio.phys_addr = fault_addr;
> run->mmio.len = len;
>
> + if (!ret) {
> + /* We handled the access successfully in the kernel. */
> + vcpu->stat.mmio_exit_kernel++;
> + kvm_riscv_vcpu_mmio_return(vcpu, run);
> + return 1;
> + }
> +
> + /* Exit to userspace for MMIO emulation */
> + vcpu->stat.mmio_exit_user++;
> + run->exit_reason = KVM_EXIT_MMIO;
> +
> return 0;
> }
>
> --
> 2.19.1
>
>
Regards,
Anup
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