Re: [Xen-devel] [PATCH v13 03/19] xen/pvh: Early bootup changes in PV code (v4).

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 3 Jan 2014, Konrad Rzeszutek Wilk wrote:
> From: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> 
> We don't use the filtering that 'xen_cpuid' is doing
> because the hypervisor treats 'XEN_EMULATE_PREFIX' as
> an invalid instruction. This means that all of the filtering
> will have to be done in the hypervisor/toolstack.
> 
> Without the filtering we expose to the guest the:
> 
>  - cpu topology (sockets, cores, etc);
>  - the APERF (which the generic scheduler likes to
>     use), see  5e626254206a709c6e937f3dda69bf26c7344f6f
>     "xen/setup: filter APERFMPERF cpuid feature out"
>  - and the inability to figure out whether MWAIT_LEAF
>    should be exposed or not. See
>    df88b2d96e36d9a9e325bfcd12eb45671cbbc937
>    "xen/enlighten: Disable MWAIT_LEAF so that acpi-pad won't be loaded."
>  - x2apic, see  4ea9b9aca90cfc71e6872ed3522356755162932c
>    "xen: mask x2APIC feature in PV"
> 
> We also check for vector callback early on, as it is a required
> feature. PVH also runs at default kernel IOPL.
> 
> Finally, pure PV settings are moved to a separate function that are
> only called for pure PV, ie, pv with pvmmu. They are also #ifdef
> with CONFIG_XEN_PVMMU.
> 
> Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>


>  arch/x86/xen/enlighten.c | 48 
> ++++++++++++++++++++++++++++++++++--------------
>  arch/x86/xen/setup.c     | 18 ++++++++++++------
>  2 files changed, 46 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index fa6ade7..eb0efc2 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -46,6 +46,7 @@
>  #include <xen/hvm.h>
>  #include <xen/hvc-console.h>
>  #include <xen/acpi.h>
> +#include <xen/features.h>
>  
>  #include <asm/paravirt.h>
>  #include <asm/apic.h>
> @@ -262,8 +263,9 @@ 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);
> +     pr_info("Booting paravirtualized kernel %son %s\n",
> +             xen_feature(XENFEAT_auto_translated_physmap) ?
> +                     "with PVH extensions " : "", 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)" : "");
> @@ -433,7 +435,7 @@ static void __init xen_init_cpuid_mask(void)
>  
>       ax = 1;
>       cx = 0;
> -     xen_cpuid(&ax, &bx, &cx, &dx);
> +     cpuid(1, &ax, &bx, &cx, &dx);
>  
>       xsave_mask =
>               (1 << (X86_FEATURE_XSAVE % 32)) |
> @@ -1420,6 +1422,19 @@ static void __init xen_setup_stackprotector(void)
>       pv_cpu_ops.load_gdt = xen_load_gdt;
>  }
>  
> +static void __init xen_pvh_early_guest_init(void)
> +{
> +     if (!xen_feature(XENFEAT_auto_translated_physmap))
> +             return;
> +
> +     if (xen_feature(XENFEAT_hvm_callback_vector))
> +             xen_have_vector_callback = 1;
> +
> +#ifdef CONFIG_X86_32
> +     BUG(); /* PVH: Implement proper support. */
> +#endif
> +}
> +
>  /* First C function to be called on Xen boot */
>  asmlinkage void __init xen_start_kernel(void)
>  {
> @@ -1431,13 +1446,16 @@ asmlinkage void __init xen_start_kernel(void)
>  
>       xen_domain_type = XEN_PV_DOMAIN;
>  
> +     xen_setup_features();
> +     xen_pvh_early_guest_init();
>       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 = xen_cpu_ops;
>  
>       x86_init.resources.memory_setup = xen_memory_setup;
>       x86_init.oem.arch_setup = xen_arch_setup;
> @@ -1469,8 +1487,6 @@ 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();
> @@ -1548,14 +1564,18 @@ asmlinkage void __init xen_start_kernel(void)
>       /* set the limit of our address space */
>       xen_reserve_top();
>  
> -     /* We used to do this in xen_arch_setup, but that is too late on AMD
> -      * were early_cpu_init (run before ->arch_setup()) calls early_amd_init
> -      * which pokes 0xcf8 port.
> -      */
> -     set_iopl.iopl = 1;
> -     rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
> -     if (rc != 0)
> -             xen_raw_printk("physdev_op failed %d\n", rc);
> +     /* PVH: runs at default kernel iopl of 0 */
> +     if (!xen_pvh_domain()) {
> +             /*
> +              * We used to do this in xen_arch_setup, but that is too late
> +              * on AMD were early_cpu_init (run before ->arch_setup()) calls
> +              * early_amd_init which pokes 0xcf8 port.
> +              */
> +             set_iopl.iopl = 1;
> +             rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
> +             if (rc != 0)
> +                     xen_raw_printk("physdev_op failed %d\n", rc);
> +     }
>  
>  #ifdef CONFIG_X86_32
>       /* set up basic CPUID stuff */
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index 68c054f..2137c51 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -563,16 +563,13 @@ void xen_enable_nmi(void)
>               BUG();
>  #endif
>  }
> -void __init xen_arch_setup(void)
> +void __init xen_pvmmu_arch_setup(void)
>  {
> -     xen_panic_handler_init();
> -
>       HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
>       HYPERVISOR_vm_assist(VMASST_CMD_enable, 
> VMASST_TYPE_writable_pagetables);
>  
> -     if (!xen_feature(XENFEAT_auto_translated_physmap))
> -             HYPERVISOR_vm_assist(VMASST_CMD_enable,
> -                                  VMASST_TYPE_pae_extended_cr3);
> +     HYPERVISOR_vm_assist(VMASST_CMD_enable,
> +                          VMASST_TYPE_pae_extended_cr3);
>  
>       if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
>           register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
> @@ -581,6 +578,15 @@ void __init xen_arch_setup(void)
>       xen_enable_sysenter();
>       xen_enable_syscall();
>       xen_enable_nmi();
> +}
> +
> +/* This function is not called for HVM domains */
> +void __init xen_arch_setup(void)
> +{
> +     xen_panic_handler_init();
> +     if (!xen_feature(XENFEAT_auto_translated_physmap))
> +             xen_pvmmu_arch_setup();
> +
>  #ifdef CONFIG_ACPI
>       if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
>               printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
> -- 
> 1.8.3.1
> 

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