Re: [[RFC PATCH 2/8]: PVH: changes related to initial boot and irq rewiring

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Aug 15, 2012 at 06:01:31PM -0700, Mukesh Rathor wrote:
> 
> ---
>  arch/x86/xen/enlighten.c |   67 ++++++++++++++++++++++++++++++++++++++-------
>  arch/x86/xen/irq.c       |   22 ++++++++++++++-
>  2 files changed, 77 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index bf4bda6..3a58c51 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -139,6 +139,8 @@ struct tls_descs {
>   */
>  static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
>  
> +static void __init xen_hvm_init_shared_info(void);
> +
>  static void clamp_max_cpus(void)
>  {
>  #ifdef CONFIG_SMP
> @@ -217,8 +219,8 @@ static void __init xen_banner(void)
>  	struct xen_extraversion extra;
>  	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
>  
> -	printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
> -	       pv_info.name);
> +	printk(KERN_INFO "Booting paravirtualized kernel %son %s\n",
> +		(xen_pvh_domain() ? "in HVM " : ""), pv_info.name);
>  	printk(KERN_INFO "Xen version: %d.%d%s%s\n",
>  	       version >> 16, version & 0xffff, extra.extraversion,
>  	       xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
> @@ -271,12 +273,15 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
>  		break;
>  	}
>  
> -	asm(XEN_EMULATE_PREFIX "cpuid"
> -		: "=a" (*ax),
> -		  "=b" (*bx),
> -		  "=c" (*cx),
> -		  "=d" (*dx)
> -		: "0" (*ax), "2" (*cx));
> +	if (xen_pvh_domain())
> +		native_cpuid(ax, bx, cx, dx);
> +	else
> +		asm(XEN_EMULATE_PREFIX "cpuid"
> +			: "=a" (*ax),
> +			"=b" (*bx),
> +			"=c" (*cx),
> +			"=d" (*dx)
> +			: "0" (*ax), "2" (*cx));
>  
>  	*bx &= maskebx;
>  	*cx &= maskecx;
> @@ -1034,6 +1039,10 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
>  
>  void xen_setup_shared_info(void)
>  {
> +	/* do later in xen_pvh_guest_init() when extend_brk is properly setup*/
> +	if (xen_pvh_domain() && xen_initial_domain())
> +		return;
> +
>  	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
>  		set_fixmap(FIX_PARAVIRT_BOOTMAP,
>  			   xen_start_info->shared_info);
> @@ -1044,6 +1053,10 @@ void xen_setup_shared_info(void)
>  		HYPERVISOR_shared_info =
>  			(struct shared_info *)__va(xen_start_info->shared_info);
>  
> +	/* PVH TBD/FIXME: vcpu info placement in phase 2 */
> +	if (xen_pvh_domain())
> +		return;
> +
>  #ifndef CONFIG_SMP
>  	/* In UP this is as good a place as any to set up shared info */
>  	xen_setup_vcpu_info_placement();
> @@ -1274,6 +1287,10 @@ static const struct machine_ops xen_machine_ops __initconst = {
>   */
>  static void __init xen_setup_stackprotector(void)
>  {
> +	if (xen_pvh_domain()) {
> +		switch_to_new_gdt(0);
> +		return;
> +	}
>  	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
>  	pv_cpu_ops.load_gdt = xen_load_gdt_boot;
>  
> @@ -1284,6 +1301,25 @@ static void __init xen_setup_stackprotector(void)
>  	pv_cpu_ops.load_gdt = xen_load_gdt;
>  }
>  
> +static void __init xen_pvh_guest_init(void)
> +{
> +#ifndef __HAVE_ARCH_PTE_SPECIAL
> +	("__HAVE_ARCH_PTE_SPECIAL is required for PVH for now\n");
> +	#error("__HAVE_ARCH_PTE_SPECIAL is required for PVH\n");
> +#endif

Should this be just rolled in the Kconfig as part of enabling
this mode?

> +	/* PVH TBD/FIXME: for now just disable this. */
> +	have_vcpu_info_placement = 0;
> +
> +	if (xen_feature(XENFEAT_hvm_callback_vector))
> +		xen_have_vector_callback = 1;
> +
> +        /* for domU, the library sets start_info.shared_info to pfn, but for
> +         * dom0, it contains mfn. we need to get the pfn for shared_info. PVH
> +	 * uses HVM code in many places */
> +	if (xen_initial_domain())
> +		xen_hvm_init_shared_info();
> +}
> +
>  /* First C function to be called on Xen boot */
>  asmlinkage void __init xen_start_kernel(void)
>  {
> @@ -1294,15 +1330,23 @@ asmlinkage void __init xen_start_kernel(void)
>  	if (!xen_start_info)
>  		return;
>  
> +#ifdef CONFIG_X86_32
> +	xen_raw_printk("ERROR: 32bit PV guest can not run in HVM container\n");
> +	return;

Perhaps BUG() ?
> +#endif
>  	xen_domain_type = XEN_PV_DOMAIN;
>  
> +	xen_setup_features();
>  	xen_setup_machphys_mapping();
>  
>  	/* Install Xen paravirt ops */
>  	pv_info = xen_info;
>  	pv_init_ops = xen_init_ops;
> -	pv_cpu_ops = xen_cpu_ops;
>  	pv_apic_ops = xen_apic_ops;
> +	if (xen_pvh_domain())
> +		pv_cpu_ops.cpuid = xen_cpuid;
> +	else
> +		pv_cpu_ops = xen_cpu_ops;
>  
>  	x86_init.resources.memory_setup = xen_memory_setup;
>  	x86_init.oem.arch_setup = xen_arch_setup;
> @@ -1334,8 +1378,6 @@ asmlinkage void __init xen_start_kernel(void)
>  	/* Work out if we support NX */
>  	x86_configure_nx();
>  
> -	xen_setup_features();
> -
>  	/* Get mfn list */
>  	if (!xen_feature(XENFEAT_auto_translated_physmap))
>  		xen_build_dynamic_phys_to_machine();
> @@ -1462,6 +1504,9 @@ asmlinkage void __init xen_start_kernel(void)
>  
>  	xen_setup_runstate_info(0);
>  
> +	if (xen_pvh_domain())
> +		xen_pvh_guest_init();
> +
>  	/* Start the world */
>  #ifdef CONFIG_X86_32
>  	i386_start_kernel();
> diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
> index 1573376..7c7dfd1 100644
> --- a/arch/x86/xen/irq.c
> +++ b/arch/x86/xen/irq.c
> @@ -100,6 +100,10 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
>  
>  static void xen_safe_halt(void)
>  {
> +	/* so event channel can be delivered to us, since in HVM container */
> +	if (xen_pvh_domain())
> +		local_irq_enable();
> +
>  	/* Blocking includes an implicit local_irq_enable(). */
>  	if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
>  		BUG();
> @@ -126,8 +130,24 @@ static const struct pv_irq_ops xen_irq_ops __initconst = {
>  #endif
>  };
>  
> +static const struct pv_irq_ops xen_pvh_irq_ops __initdata = {
> +	.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
> +	.restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
> +	.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
> +	.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
> +
> +	.safe_halt = xen_safe_halt,
> +	.halt = xen_halt,
> +#ifdef CONFIG_X86_64
> +	.adjust_exception_frame = paravirt_nop,
> +#endif
> +};
> +
>  void __init xen_init_irq_ops(void)
>  {
> -	pv_irq_ops = xen_irq_ops;
> +	if (xen_pvh_domain())
> +		pv_irq_ops = xen_pvh_irq_ops;
> +	else
> +		pv_irq_ops = xen_irq_ops;
>  	x86_init.irqs.intr_init = xen_init_IRQ;
>  }
> -- 
> 1.7.2.3