Re: [PATCH v13 29/30] LoongArch: KVM: Supplement kvm document about LoongArch-specific part

From: Huacai Chen
Date: Thu Jun 15 2023 - 05:42:28 EST

Hi, Tianrui,

On Fri, Jun 9, 2023 at 5:09 PM Tianrui Zhao <zhaotianrui@xxxxxxxxxxx> wrote:
>
> Supplement kvm document about LoongArch-specific part, such as add
> api introduction for GET/SET_ONE_REG, GET/SET_FPU, GET/SET_MP_STATE,
> etc.
>
> Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
> ---
> Documentation/virt/kvm/api.rst | 71 +++++++++++++++++++++++++++++-----
> 1 file changed, 62 insertions(+), 9 deletions(-)
>
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index add067793b90..ad8e13eab48d 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -416,6 +416,12 @@ Reads the general purpose registers from the vcpu.
> __u64 pc;
> };
>
> + /* LoongArch */
> + struct kvm_regs {
Add a " /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */" line as others here?

> + unsigned long gpr[32];
> + unsigned long pc;
> + };
> +
>
> 4.12 KVM_SET_REGS
> -----------------
> @@ -506,7 +512,7 @@ translation mode.
> ------------------
>
> :Capability: basic
> -:Architectures: x86, ppc, mips, riscv
> +:Architectures: x86, ppc, mips, riscv, loongarch
> :Type: vcpu ioctl
> :Parameters: struct kvm_interrupt (in)
> :Returns: 0 on success, negative on failure.
> @@ -592,6 +598,14 @@ b) KVM_INTERRUPT_UNSET
>
> This is an asynchronous vcpu ioctl and can be invoked from any thread.
>
> +LOONGARCH:
> +^^^^^^^^^^
> +
> +Queues an external interrupt to be injected into the virtual CPU. A negative
> +interrupt number dequeues the interrupt.
> +
> +This is an asynchronous vcpu ioctl and can be invoked from any thread.
> +
>
> 4.17 KVM_DEBUG_GUEST
> --------------------
> @@ -737,7 +751,7 @@ signal mask.
> ----------------
>
> :Capability: basic
> -:Architectures: x86
> +:Architectures: x86, loongarch
> :Type: vcpu ioctl
> :Parameters: struct kvm_fpu (out)
> :Returns: 0 on success, -1 on error
> @@ -746,7 +760,7 @@ Reads the floating point state from the vcpu.
>
> ::
>
> - /* for KVM_GET_FPU and KVM_SET_FPU */
> + /* x86: for KVM_GET_FPU and KVM_SET_FPU */
> struct kvm_fpu {
> __u8 fpr[8][16];
> __u16 fcw;
> @@ -761,12 +775,22 @@ Reads the floating point state from the vcpu.
> __u32 pad2;
> };
>
> + /* LoongArch: for KVM_GET_FPU and KVM_SET_FPU */
> + struct kvm_fpu {
> + __u32 fcsr;
> + __u32 none;
Maybe use pad1 as x86 is better.

Huacai
> + __u64 fcc;
> + struct kvm_fpureg {
> + __u64 val64[4];
> + }fpr[32];
> + };
> +
>
> 4.23 KVM_SET_FPU
> ----------------
>
> :Capability: basic
> -:Architectures: x86
> +:Architectures: x86, loongarch
> :Type: vcpu ioctl
> :Parameters: struct kvm_fpu (in)
> :Returns: 0 on success, -1 on error
> @@ -775,7 +799,7 @@ Writes the floating point state to the vcpu.
>
> ::
>
> - /* for KVM_GET_FPU and KVM_SET_FPU */
> + /* x86: for KVM_GET_FPU and KVM_SET_FPU */
> struct kvm_fpu {
> __u8 fpr[8][16];
> __u16 fcw;
> @@ -790,6 +814,16 @@ Writes the floating point state to the vcpu.
> __u32 pad2;
> };
>
> + /* LoongArch: for KVM_GET_FPU and KVM_SET_FPU */
> + struct kvm_fpu {
> + __u32 fcsr;
> + __u32 none;
> + __u64 fcc;
> + struct kvm_fpureg {
> + __u64 val64[4];
> + }fpr[32];
> + };
> +
>
> 4.24 KVM_CREATE_IRQCHIP
> -----------------------
> @@ -1387,7 +1421,7 @@ documentation when it pops into existence).
> -------------------
>
> :Capability: KVM_CAP_ENABLE_CAP
> -:Architectures: mips, ppc, s390, x86
> +:Architectures: mips, ppc, s390, x86, loongarch
> :Type: vcpu ioctl
> :Parameters: struct kvm_enable_cap (in)
> :Returns: 0 on success; -1 on error
> @@ -1442,7 +1476,7 @@ for vm-wide capabilities.
> ---------------------
>
> :Capability: KVM_CAP_MP_STATE
> -:Architectures: x86, s390, arm64, riscv
> +:Architectures: x86, s390, arm64, riscv, loongarch
> :Type: vcpu ioctl
> :Parameters: struct kvm_mp_state (out)
> :Returns: 0 on success; -1 on error
> @@ -1460,7 +1494,7 @@ Possible values are:
>
> ========================== ===============================================
> KVM_MP_STATE_RUNNABLE the vcpu is currently running
> - [x86,arm64,riscv]
> + [x86,arm64,riscv,loongarch]
> KVM_MP_STATE_UNINITIALIZED the vcpu is an application processor (AP)
> which has not yet received an INIT signal [x86]
> KVM_MP_STATE_INIT_RECEIVED the vcpu has received an INIT signal, and is
> @@ -1516,11 +1550,14 @@ For riscv:
> The only states that are valid are KVM_MP_STATE_STOPPED and
> KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not.
>
> +On LoongArch, only the KVM_MP_STATE_RUNNABLE state is used to reflect
> +whether the vcpu is runnable.
> +
> 4.39 KVM_SET_MP_STATE
> ---------------------
>
> :Capability: KVM_CAP_MP_STATE
> -:Architectures: x86, s390, arm64, riscv
> +:Architectures: x86, s390, arm64, riscv, loongarch
> :Type: vcpu ioctl
> :Parameters: struct kvm_mp_state (in)
> :Returns: 0 on success; -1 on error
> @@ -1538,6 +1575,9 @@ For arm64/riscv:
> The only states that are valid are KVM_MP_STATE_STOPPED and
> KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not.
>
> +On LoongArch, only the KVM_MP_STATE_RUNNABLE state is used to reflect
> +whether the vcpu is runnable.
> +
> 4.40 KVM_SET_IDENTITY_MAP_ADDR
> ------------------------------
>
> @@ -2839,6 +2879,19 @@ Following are the RISC-V D-extension registers:
> 0x8020 0000 0600 0020 fcsr Floating point control and status register
> ======================= ========= =============================================
>
> +LoongArch registers are mapped using the lower 32 bits. The upper 16 bits of
> +that is the register group type.
> +
> +LoongArch csr registers are used to control guest cpu or get status of guest
> +cpu, and they have the following id bit patterns::
> +
> + 0x9030 0000 0001 00 <reg:5> <sel:3> (64-bit)
> +
> +LoongArch KVM control registers are used to implement some new defined functions
> +such as set vcpu counter or reset vcpu, and they have the following id bit patterns::
> +
> + 0x9030 0000 0002 <reg:16>
> +
>
> 4.69 KVM_GET_ONE_REG
> --------------------
> --
> 2.39.1
>
>