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    Subject[PATCH 4/7] xen/hvm: Xen PV extension of HVM initialization
    Date
    The PV extended HVM(once known as Hybrid) is started from real mode like
    HVM guest, but also with a component based PV feature selection(e.g. PV halt,
    PV timer, event channel, then PV drivers). So guest can takes the advantages
    of both H/W virtualization and Para-Virtualization.

    This patch introduced the PV extension of HVM guest initialization.

    Guest would detect the capability using CPUID 0x40000002.edx, then call
    HVMOP_enable_pv hypercall to enable pv support in hypervisor.

    Signed-off-by: Sheng Yang <sheng@linux.intel.com>
    Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
    ---
    arch/x86/include/asm/xen/cpuid.h | 5 ++
    arch/x86/xen/Kconfig | 8 ++
    arch/x86/xen/Makefile | 1 +
    arch/x86/xen/hvmpv.c | 133 ++++++++++++++++++++++++++++++++++++
    include/xen/interface/hvm/hvm_op.h | 8 ++
    include/xen/xen.h | 9 +++
    6 files changed, 164 insertions(+), 0 deletions(-)
    create mode 100644 arch/x86/xen/hvmpv.c

    diff --git a/arch/x86/include/asm/xen/cpuid.h b/arch/x86/include/asm/xen/cpuid.h
    index 8787f03..a93c851 100644
    --- a/arch/x86/include/asm/xen/cpuid.h
    +++ b/arch/x86/include/asm/xen/cpuid.h
    @@ -65,4 +65,9 @@
    #define _XEN_CPUID_FEAT1_MMU_PT_UPDATE_PRESERVE_AD 0
    #define XEN_CPUID_FEAT1_MMU_PT_UPDATE_PRESERVE_AD (1u<<0)

    +#define _XEN_CPUID_FEAT2_HVM_PV 0
    +#define XEN_CPUID_FEAT2_HVM_PV (1u<<0)
    +#define _XEN_CPUID_FEAT2_HVM_PV_EVTCHN 1
    +#define XEN_CPUID_FEAT2_HVM_PV_EVTCHN (1u<<1)
    +
    #endif /* __XEN_PUBLIC_ARCH_X86_CPUID_H__ */
    diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
    index b83e119..af3c7a0 100644
    --- a/arch/x86/xen/Kconfig
    +++ b/arch/x86/xen/Kconfig
    @@ -36,3 +36,11 @@ config XEN_DEBUG_FS
    help
    Enable statistics output and various tuning options in debugfs.
    Enabling this option may incur a significant performance overhead.
    +
    +config XEN_HVM_PV
    + bool "PV extension of HVM"
    + depends on XEN && X86_64
    + default n
    + help
    + Enable the PV extension of HVM, so that HVM guest would benefit from
    + PV features like PV timer and evtchn.
    diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
    index 3bb4fc2..73bd5db 100644
    --- a/arch/x86/xen/Makefile
    +++ b/arch/x86/xen/Makefile
    @@ -17,4 +17,5 @@ obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \
    obj-$(CONFIG_SMP) += smp.o
    obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o
    obj-$(CONFIG_XEN_DEBUG_FS) += debugfs.o
    +obj-$(CONFIG_XEN_HVM_PV) += hvmpv.o

    diff --git a/arch/x86/xen/hvmpv.c b/arch/x86/xen/hvmpv.c
    new file mode 100644
    index 0000000..7a741ed
    --- /dev/null
    +++ b/arch/x86/xen/hvmpv.c
    @@ -0,0 +1,133 @@
    +/*
    + * PV extension of HVM implementation.
    + *
    + * Sheng Yang <sheng@linux.intel.com>, Intel Corporation, 2010
    + *
    + */
    +#include <linux/kernel.h>
    +#include <linux/init.h>
    +#include <linux/percpu.h>
    +#include <linux/module.h>
    +
    +#include <xen/xen.h>
    +#include <xen/features.h>
    +#include <xen/events.h>
    +#include <xen/hvm.h>
    +#include <xen/interface/xen.h>
    +#include <xen/interface/version.h>
    +#include <xen/interface/memory.h>
    +
    +#include <asm/xen/cpuid.h>
    +#include <asm/xen/hypercall.h>
    +#include <asm/xen/hypervisor.h>
    +
    +#include "xen-ops.h"
    +
    +u32 xen_hvm_pv_features;
    +EXPORT_SYMBOL_GPL(xen_hvm_pv_features);
    +
    +static const struct pv_info xen_hvm_pv_info __initdata = {
    + .paravirt_enabled = 1,
    + .shared_kernel_pmd = 0,
    + .kernel_rpl = 0,
    + .name = "Xen",
    +};
    +
    +static void __init xen_hvm_pv_banner(void)
    +{
    + unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
    + struct xen_extraversion extra;
    + HYPERVISOR_xen_version(XENVER_extraversion, &extra);
    +
    + printk(KERN_INFO "Booting PV extended HVM kernel on %s\n",
    + pv_info.name);
    + printk(KERN_INFO "Xen version: %d.%d%s\n",
    + version >> 16, version & 0xffff, extra.extraversion);
    +}
    +
    +static int __init xen_para_available(void)
    +{
    + uint32_t eax, ebx, ecx, edx;
    + cpuid(XEN_CPUID_LEAF(0), &eax, &ebx, &ecx, &edx);
    +
    + if (ebx == XEN_CPUID_SIGNATURE_EBX &&
    + ecx == XEN_CPUID_SIGNATURE_ECX &&
    + edx == XEN_CPUID_SIGNATURE_EDX &&
    + ((eax - XEN_CPUID_LEAF(0)) >= 2))
    + return 1;
    +
    + return 0;
    +}
    +
    +static int __init enable_hvm_pv(u64 flags)
    +{
    + struct xen_hvm_pv_type a;
    +
    + a.domid = DOMID_SELF;
    + a.flags = flags;
    + return HYPERVISOR_hvm_op(HVMOP_enable_pv, &a);
    +}
    +
    +static int __init init_hvm_pv_info(void)
    +{
    + uint32_t ecx, edx, pages, msr;
    + u64 pfn;
    +
    + if (!xen_para_available())
    + return -EINVAL;
    +
    + cpuid(XEN_CPUID_LEAF(2), &pages, &msr, &ecx, &edx);
    +
    + /* Check if hvm_pv mode is supported */
    + if (!(edx & XEN_CPUID_FEAT2_HVM_PV))
    + return -ENODEV;
    +
    + /* We only support 1 page of hypercall for now */
    + if (pages != 1)
    + return -ENOMEM;
    +
    + pfn = __pa(hypercall_page);
    + wrmsrl(msr, pfn);
    +
    + xen_setup_features();
    +
    + x86_init.oem.banner = xen_hvm_pv_banner;
    + pv_info = xen_hvm_pv_info;
    +
    + xen_domain_type = XEN_HVM_DOMAIN;
    +
    + return 0;
    +}
    +
    +static struct shared_info shared_info_page __page_aligned_bss;
    +
    +static void __init init_shared_info(void)
    +{
    + struct xen_add_to_physmap xatp;
    +
    + xatp.domid = DOMID_SELF;
    + xatp.idx = 0;
    + xatp.space = XENMAPSPACE_shared_info;
    + xatp.gpfn = __pa(&shared_info_page) >> PAGE_SHIFT;
    + if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
    + BUG();
    +
    + HYPERVISOR_shared_info = (struct shared_info *)&shared_info_page;
    +
    + per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
    +}
    +
    +void __init xen_guest_init(void)
    +{
    + int r;
    +
    + /* Ensure the we won't confused with others */
    + if (xen_domain_type != XEN_NATIVE)
    + return;
    +
    + r = init_hvm_pv_info();
    + if (r < 0)
    + return;
    +
    + init_shared_info();
    +}
    diff --git a/include/xen/interface/hvm/hvm_op.h b/include/xen/interface/hvm/hvm_op.h
    index 7c74ba4..3f0b118 100644
    --- a/include/xen/interface/hvm/hvm_op.h
    +++ b/include/xen/interface/hvm/hvm_op.h
    @@ -69,4 +69,12 @@ DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_set_pci_link_route);
    /* Flushes all VCPU TLBs: @arg must be NULL. */
    #define HVMOP_flush_tlbs 5

    +#define HVMOP_enable_pv 9
    +struct xen_hvm_pv_type {
    + domid_t domid;
    + uint32_t flags;
    +#define HVM_PV_CLOCK (1ull<<0)
    +#define HVM_PV_EVTCHN (1ull<<1)
    +};
    +
    #endif /* __XEN_PUBLIC_HVM_HVM_OP_H__ */
    diff --git a/include/xen/xen.h b/include/xen/xen.h
    index a164024..11f5ced 100644
    --- a/include/xen/xen.h
    +++ b/include/xen/xen.h
    @@ -19,6 +19,15 @@ extern enum xen_domain_type xen_domain_type;
    #define xen_hvm_domain() (xen_domain() && \
    xen_domain_type == XEN_HVM_DOMAIN)

    +#ifdef CONFIG_XEN_HVM_PV
    +
    +#define XEN_HVM_PV_EVTCHN_ENABLED (1u << 1)
    +extern u32 xen_hvm_pv_features;
    +
    +#define xen_hvm_pv_evtchn_enabled() \
    + (xen_hvm_pv_features & XEN_HVM_PV_EVTCHN_ENABLED)
    +#endif /* CONFIG_XEN_HVM_PV */
    +
    #ifdef CONFIG_XEN_DOM0
    #include <xen/interface/xen.h>
    #include <asm/xen/hypervisor.h>
    --
    1.5.4.5


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