Re: [PATCH v2 01/21] x86/xen: separate PV and HVM hypervisors

[Juergen Gross]

On 02/03/17 18:53, Vitaly Kuznetsov wrote:
> As a preparation to splitting the code we need to untangle it:
> 
> x86_hyper_xen -> x86_hyper_xen_hvm and x86_hyper_xen_pv
> xen_platform() -> xen_platform_hvm() and xen_platform_pv()
> xen_cpu_up_prepare() -> xen_cpu_up_prepare_pv() and xen_cpu_up_prepare_hvm()
> xen_cpu_dead() -> xen_cpu_dead_pv() and xen_cpu_dead_pv_hvm()
> 
> Add two parameters to xen_cpuhp_setup() to pass proper cpu_up_prepare and
> cpu_dead hooks. xen_set_cpu_features() is now PV-only so the redundant
> xen_pv_domain() check can be dropped.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
>  arch/x86/include/asm/hypervisor.h |   3 +-
>  arch/x86/kernel/cpu/hypervisor.c  |   3 +-
>  arch/x86/xen/enlighten.c          | 113 +++++++++++++++++++++++++-------------
>  3 files changed, 78 insertions(+), 41 deletions(-)
> 
> diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
> index 67942b6..6f7545c6 100644
> --- a/arch/x86/include/asm/hypervisor.h
> +++ b/arch/x86/include/asm/hypervisor.h
> @@ -53,7 +53,8 @@ extern const struct hypervisor_x86 *x86_hyper;
>  /* Recognized hypervisors */
>  extern const struct hypervisor_x86 x86_hyper_vmware;
>  extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
> -extern const struct hypervisor_x86 x86_hyper_xen;
> +extern const struct hypervisor_x86 x86_hyper_xen_pv;
> +extern const struct hypervisor_x86 x86_hyper_xen_hvm;
>  extern const struct hypervisor_x86 x86_hyper_kvm;
>  
>  extern void init_hypervisor(struct cpuinfo_x86 *c);
> diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
> index 35691a6..a77f18d 100644
> --- a/arch/x86/kernel/cpu/hypervisor.c
> +++ b/arch/x86/kernel/cpu/hypervisor.c
> @@ -29,7 +29,8 @@
>  static const __initconst struct hypervisor_x86 * const hypervisors[] =
>  {
>  #ifdef CONFIG_XEN
> -	&x86_hyper_xen,
> +	&x86_hyper_xen_pv,
> +	&x86_hyper_xen_hvm,
>  #endif
>  	&x86_hyper_vmware,
>  	&x86_hyper_ms_hyperv,
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index ec1d5c4..4c1a582 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -139,9 +139,11 @@ void *xen_initial_gdt;
>  
>  RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
>  
> -static int xen_cpu_up_prepare(unsigned int cpu);
> +static int xen_cpu_up_prepare_pv(unsigned int cpu);
> +static int xen_cpu_up_prepare_hvm(unsigned int cpu);
>  static int xen_cpu_up_online(unsigned int cpu);
> -static int xen_cpu_dead(unsigned int cpu);
> +static int xen_cpu_dead_pv(unsigned int cpu);
> +static int xen_cpu_dead_hvm(unsigned int cpu);
>  
>  /*
>   * Point at some empty memory to start with. We map the real shared_info
> @@ -1447,13 +1449,14 @@ static void __init xen_dom0_set_legacy_features(void)
>  	x86_platform.legacy.rtc = 1;
>  }
>  
> -static int xen_cpuhp_setup(void)
> +static int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int),
> +			   int (*cpu_dead_cb)(unsigned int))
>  {
>  	int rc;
>  
>  	rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE,
>  				       "x86/xen/hvm_guest:prepare",
> -				       xen_cpu_up_prepare, xen_cpu_dead);
> +				       cpu_up_prepare_cb, cpu_dead_cb);
>  	if (rc >= 0) {
>  		rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
>  					       "x86/xen/hvm_guest:online",
> @@ -1559,7 +1562,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
>  	   possible map and a non-dummy shared_info. */
>  	per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
>  
> -	WARN_ON(xen_cpuhp_setup());
> +	WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv));
>  
>  	local_irq_disable();
>  	early_boot_irqs_disabled = true;
> @@ -1840,28 +1843,41 @@ static void __init init_hvm_pv_info(void)
>  }
>  #endif
>  
> -static int xen_cpu_up_prepare(unsigned int cpu)
> +static int xen_cpu_up_prepare_pv(unsigned int cpu)
>  {
>  	int rc;
>  
> -	if (xen_hvm_domain()) {
> -		/*
> -		 * This can happen if CPU was offlined earlier and
> -		 * offlining timed out in common_cpu_die().
> -		 */
> -		if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
> -			xen_smp_intr_free(cpu);
> -			xen_uninit_lock_cpu(cpu);
> -		}
> +	xen_setup_timer(cpu);
>  
> -		if (cpu_acpi_id(cpu) != U32_MAX)
> -			per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
> -		else
> -			per_cpu(xen_vcpu_id, cpu) = cpu;
> -		xen_vcpu_setup(cpu);
> +	rc = xen_smp_intr_init(cpu);
> +	if (rc) {
> +		WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
> +		     cpu, rc);
> +		return rc;
> +	}
> +	return 0;
> +}
> +
> +static int xen_cpu_up_prepare_hvm(unsigned int cpu)
> +{
> +	int rc;
> +
> +	/*
> +	 * This can happen if CPU was offlined earlier and
> +	 * offlining timed out in common_cpu_die().
> +	 */
> +	if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
> +		xen_smp_intr_free(cpu);
> +		xen_uninit_lock_cpu(cpu);
>  	}
>  
> -	if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
> +	if (cpu_acpi_id(cpu) != U32_MAX)
> +		per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
> +	else
> +		per_cpu(xen_vcpu_id, cpu) = cpu;
> +	xen_vcpu_setup(cpu);
> +
> +	if (xen_feature(XENFEAT_hvm_safe_pvclock))
>  		xen_setup_timer(cpu);
>  
>  	rc = xen_smp_intr_init(cpu);
> @@ -1873,16 +1889,25 @@ static int xen_cpu_up_prepare(unsigned int cpu)
>  	return 0;
>  }
>  
> -static int xen_cpu_dead(unsigned int cpu)
> +static int xen_cpu_dead_pv(unsigned int cpu)
>  {
>  	xen_smp_intr_free(cpu);
>  
> -	if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
> -		xen_teardown_timer(cpu);
> +	xen_teardown_timer(cpu);
>  
>  	return 0;
>  }
>  
> +static int xen_cpu_dead_hvm(unsigned int cpu)
> +{
> +	xen_smp_intr_free(cpu);
> +
> +	if (xen_feature(XENFEAT_hvm_safe_pvclock))
> +		xen_teardown_timer(cpu);
> +
> +       return 0;
> +}
> +
>  static int xen_cpu_up_online(unsigned int cpu)
>  {
>  	xen_init_lock_cpu(cpu);
> @@ -1919,7 +1944,7 @@ static void __init xen_hvm_guest_init(void)
>  	BUG_ON(!xen_feature(XENFEAT_hvm_callback_vector));
>  
>  	xen_hvm_smp_init();
> -	WARN_ON(xen_cpuhp_setup());
> +	WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
>  	xen_unplug_emulated_devices();
>  	x86_init.irqs.intr_init = xen_init_IRQ;
>  	xen_hvm_init_time_ops();
> @@ -1942,9 +1967,17 @@ static __init int xen_parse_nopv(char *arg)
>  }
>  early_param("xen_nopv", xen_parse_nopv);
>  
> -static uint32_t __init xen_platform(void)
> +static uint32_t __init xen_platform_pv(void)
>  {
> -	if (xen_nopv)
> +	if (xen_pv_domain())
> +		return xen_cpuid_base();
> +
> +	return 0;
> +}
> +
> +static uint32_t __init xen_platform_hvm(void)
> +{
> +	if (xen_pv_domain() || xen_nopv)
>  		return 0;
>  
>  	return xen_cpuid_base();
> @@ -1966,10 +1999,8 @@ EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
>  
>  static void xen_set_cpu_features(struct cpuinfo_x86 *c)
>  {
> -	if (xen_pv_domain()) {
> -		clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
> -		set_cpu_cap(c, X86_FEATURE_XENPV);
> -	}
> +	clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
> +	set_cpu_cap(c, X86_FEATURE_XENPV);
>  }
>  
>  static void xen_pin_vcpu(int cpu)
> @@ -2011,17 +2042,21 @@ static void xen_pin_vcpu(int cpu)
>  	}
>  }
>  
> -const struct hypervisor_x86 x86_hyper_xen = {
> -	.name			= "Xen",
> -	.detect			= xen_platform,
> -#ifdef CONFIG_XEN_PVHVM
> -	.init_platform		= xen_hvm_guest_init,
> -#endif
> -	.x2apic_available	= xen_x2apic_para_available,
> +const struct hypervisor_x86 x86_hyper_xen_pv = {
> +	.name                   = "Xen PV",
> +	.detect                 = xen_platform_pv,
>  	.set_cpu_features       = xen_set_cpu_features,
>  	.pin_vcpu               = xen_pin_vcpu,
>  };
> -EXPORT_SYMBOL(x86_hyper_xen);
> +EXPORT_SYMBOL(x86_hyper_xen_pv);
> +
> +const struct hypervisor_x86 x86_hyper_xen_hvm = {
> +	.name                   = "Xen HVM",
> +	.detect                 = xen_platform_hvm,
> +	.init_platform          = xen_hvm_guest_init,
> +	.x2apic_available       = xen_x2apic_para_available,

Please keep the .pin_vcpu member. It will be needed for a PVH dom0.


Juergen