Messages in this thread | | | Date | Tue, 10 Nov 2020 21:14:19 +0800 | From | Shuo A Liu <> | Subject | Re: [PATCH v5 07/17] virt: acrn: Introduce an ioctl to set vCPU registers state |
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Hi Greg,
On Mon 9.Nov'20 at 18:09:40 +0100, Greg Kroah-Hartman wrote: >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?
The hypervisor need a Guest Physical Address to access the data, so virt_to_phys() is used here.
>And there really is no validation of >any fields?
Yes. Because HSM driver has little knowledge to do the validation.
> >> + 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?
The device is just for dev_*() usage. The driver links all active VMs in a global list acrn_vm_list. And also the notification interrupt (hypervisor to Service VM) is global. So, there is only one device.
> > > >> + "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?
The hypervisor and the driver only support X86_64 platform for now. So, the endian should be certain.
> > > >> + __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?
To keep same layout with the hypervisor. Because the structure will be passed to hypervisor directly.
> >Is there a pointer to a public document for all of these structures >somewhere?
Unfortunately, no. I have added some documents for some strutures in the code via kernel-doc format.
> >> + struct acrn_regs vcpu_regs; >> +} __attribute__((aligned(8))); > >What does the alignment do here?
The hypervisor wants to access aligned data block to improve the efficiency. Currently, the hypervisor only runs on x86_64 platform.
Thanks shuo
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