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SubjectRe: [PATCH v5 07/17] virt: acrn: Introduce an ioctl to set vCPU registers state
On Mon, Oct 19, 2020 at 02:17:53PM +0800, shuo.a.liu@intel.com wrote:
> From: Shuo Liu <shuo.a.liu@intel.com>
>
> A virtual CPU of User VM has different context due to the different
> registers state. ACRN userspace needs to set the virtual CPU
> registers state (e.g. giving a initial registers state to a virtual
> BSP of a User VM).
>
> HSM provides an ioctl ACRN_IOCTL_SET_VCPU_REGS to do the virtual CPU
> registers state setting. The ioctl passes the registers state from ACRN
> userspace to the hypervisor directly.
>
> Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
> Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
> Cc: Zhi Wang <zhi.a.wang@intel.com>
> Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
> Cc: Yu Wang <yu1.wang@intel.com>
> Cc: Reinette Chatre <reinette.chatre@intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> drivers/virt/acrn/hsm.c | 15 ++++++++
> drivers/virt/acrn/hypercall.h | 13 +++++++
> include/uapi/linux/acrn.h | 71 +++++++++++++++++++++++++++++++++++
> 3 files changed, 99 insertions(+)
>
> diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c
> index cbda67d4eb89..58ceb02e82db 100644
> --- a/drivers/virt/acrn/hsm.c
> +++ b/drivers/virt/acrn/hsm.c
> @@ -9,6 +9,7 @@
> * Yakui Zhao <yakui.zhao@intel.com>
> */
>
> +#include <linux/io.h>
> #include <linux/mm.h>
> #include <linux/module.h>
> #include <linux/slab.h>
> @@ -46,6 +47,7 @@ static long acrn_dev_ioctl(struct file *filp, unsigned int cmd,
> {
> struct acrn_vm *vm = filp->private_data;
> struct acrn_vm_creation *vm_param;
> + struct acrn_vcpu_regs *cpu_regs;
> int ret = 0;
>
> if (vm->vmid == ACRN_INVALID_VMID && cmd != ACRN_IOCTL_CREATE_VM) {
> @@ -97,6 +99,19 @@ static long acrn_dev_ioctl(struct file *filp, unsigned int cmd,
> case ACRN_IOCTL_DESTROY_VM:
> ret = acrn_vm_destroy(vm);
> break;
> + case ACRN_IOCTL_SET_VCPU_REGS:
> + cpu_regs = memdup_user((void __user *)ioctl_param,
> + sizeof(struct acrn_vcpu_regs));
> + if (IS_ERR(cpu_regs))
> + return PTR_ERR(cpu_regs);
> +
> + ret = hcall_set_vcpu_regs(vm->vmid, virt_to_phys(cpu_regs));

Why the virt_to_phys() call here? And there really is no validation of
any fields?

> + if (ret < 0)
> + dev_dbg(acrn_dev.this_device,

Wait, a global, static device? Where did I miss that? That feels odd,
why is there just one?



> + "Failed to set regs state of VM%u!\n",
> + vm->vmid);
> + kfree(cpu_regs);
> + break;
> default:
> dev_dbg(acrn_dev.this_device, "Unknown IOCTL 0x%x!\n", cmd);
> ret = -ENOTTY;
> diff --git a/drivers/virt/acrn/hypercall.h b/drivers/virt/acrn/hypercall.h
> index 426b66cadb1f..f29cfae08862 100644
> --- a/drivers/virt/acrn/hypercall.h
> +++ b/drivers/virt/acrn/hypercall.h
> @@ -19,6 +19,7 @@
> #define HC_START_VM _HC_ID(HC_ID, HC_ID_VM_BASE + 0x02)
> #define HC_PAUSE_VM _HC_ID(HC_ID, HC_ID_VM_BASE + 0x03)
> #define HC_RESET_VM _HC_ID(HC_ID, HC_ID_VM_BASE + 0x05)
> +#define HC_SET_VCPU_REGS _HC_ID(HC_ID, HC_ID_VM_BASE + 0x06)
>
> /**
> * hcall_create_vm() - Create a User VM
> @@ -75,4 +76,16 @@ static inline long hcall_reset_vm(u64 vmid)
> return acrn_hypercall1(HC_RESET_VM, vmid);
> }
>
> +/**
> + * hcall_set_vcpu_regs() - Set up registers of virtual CPU of a User VM
> + * @vmid: User VM ID
> + * @regs_state: Service VM GPA of registers state
> + *
> + * Return: 0 on success, <0 on failure
> + */
> +static inline long hcall_set_vcpu_regs(u64 vmid, u64 regs_state)
> +{
> + return acrn_hypercall2(HC_SET_VCPU_REGS, vmid, regs_state);
> +}
> +
> #endif /* __ACRN_HSM_HYPERCALL_H */
> diff --git a/include/uapi/linux/acrn.h b/include/uapi/linux/acrn.h
> index 364b1a783074..1d5b82e154fb 100644
> --- a/include/uapi/linux/acrn.h
> +++ b/include/uapi/linux/acrn.h
> @@ -36,6 +36,75 @@ struct acrn_vm_creation {
> __u8 reserved2[8];
> } __attribute__((aligned(8)));
>
> +struct acrn_gp_regs {
> + __u64 rax;
> + __u64 rcx;
> + __u64 rdx;
> + __u64 rbx;
> + __u64 rsp;
> + __u64 rbp;
> + __u64 rsi;
> + __u64 rdi;
> + __u64 r8;
> + __u64 r9;
> + __u64 r10;
> + __u64 r11;
> + __u64 r12;
> + __u64 r13;
> + __u64 r14;
> + __u64 r15;
> +};
> +
> +struct acrn_descriptor_ptr {
> + __u16 limit;
> + __u64 base;
> + __u16 reserved[3];
> +} __attribute__ ((__packed__));
> +
> +struct acrn_regs {
> + struct acrn_gp_regs gprs;
> + struct acrn_descriptor_ptr gdt;
> + struct acrn_descriptor_ptr idt;
> +
> + __u64 rip;

As these are all crossing the user/kernel boundry and then on to
somewhere "else", you have to specify the endian of all of these, right?

if not, why not?



> + __u64 cs_base;
> + __u64 cr0;
> + __u64 cr4;
> + __u64 cr3;
> + __u64 ia32_efer;
> + __u64 rflags;
> + __u64 reserved_64[4];
> +
> + __u32 cs_ar;
> + __u32 cs_limit;
> + __u32 reserved_32[3];
> +
> + __u16 cs_sel;
> + __u16 ss_sel;
> + __u16 ds_sel;
> + __u16 es_sel;
> + __u16 fs_sel;
> + __u16 gs_sel;
> + __u16 ldt_sel;
> + __u16 tr_sel;
> +
> + __u16 reserved_16[4];
> +};
> +
> +/**
> + * struct acrn_vcpu_regs - Info of vCPU registers state
> + * @vcpu_id: vCPU ID
> + * @reserved0: Reserved
> + * @vcpu_regs: vCPU registers state
> + *
> + * This structure will be passed to hypervisor directly.
> + */
> +struct acrn_vcpu_regs {
> + __u16 vcpu_id;

Endian?

> + __u16 reserved0[3];

What does the reserved fields do?

Is there a pointer to a public document for all of these structures
somewhere?

> + struct acrn_regs vcpu_regs;
> +} __attribute__((aligned(8)));

What does the alignment do here?

thanks,

greg k-h

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