Change subject to:
RISC-V: KVM: kernel mmio read/write support
Also add 1-2 sentences of commit description.
On Fri, Jul 24, 2020 at 2:25 PM Yifei Jiang <jiangyifei@xxxxxxxxxx> wrote:
>
> Signed-off-by: Yifei Jiang <jiangyifei@xxxxxxxxxx>
> Signed-off-by: Mingwang Li <limingwang@xxxxxxxxxx>
> ---
> 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);
> +
> 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);
> +
> 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
