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Subject[RFC 2/2] RISC-V: KVM: read\write kernel mmio device support
Date
Signed-off-by: Yifei Jiang <jiangyifei@huawei.com>
Signed-off-by: Mingwang Li <limingwang@huawei.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);
+
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

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