From: Wei Liu <wei.liu....@gmail.com> On Behalf Of Wei Liu Sent: Wednesday,
January 22, 2020 12:24 PM
>
> Use the top-most addressable page for that purpose. Adjust e820 code
> accordingly.
>
> We also need to register Xen's guest OS ID to Hyper-V. Use 0x300 as the
> OS type.
>
> Signed-off-by: Wei Liu <li...@microsoft.com>
> ---
> XXX the decision on Xen's vendor ID is pending.
>
> v4:
> 1. Use fixmap
> 2. Follow routines listed in TLFS
> ---
> xen/arch/x86/e820.c | 41 +++++++++++++++----
> xen/arch/x86/guest/hyperv/hyperv.c | 53 +++++++++++++++++++++++--
> xen/include/asm-x86/guest/hyperv-tlfs.h | 5 ++-
> 3 files changed, 86 insertions(+), 13 deletions(-)
>
> diff --git a/xen/arch/x86/e820.c b/xen/arch/x86/e820.c
> index 082f9928a1..5a4ef27a0b 100644
> --- a/xen/arch/x86/e820.c
> +++ b/xen/arch/x86/e820.c
> @@ -36,6 +36,22 @@ boolean_param("e820-verbose", e820_verbose);
> struct e820map e820;
> struct e820map __initdata e820_raw;
>
> +static unsigned int find_phys_addr_bits(void)
> +{
> + uint32_t eax;
> + unsigned int phys_bits = 36;
> +
> + eax = cpuid_eax(0x80000000);
> + if ( (eax >> 16) == 0x8000 && eax >= 0x80000008 )
> + {
> + phys_bits = (uint8_t)cpuid_eax(0x80000008);
> + if ( phys_bits > PADDR_BITS )
> + phys_bits = PADDR_BITS;
> + }
> +
> + return phys_bits;
> +}
> +
> /*
> * This function checks if the entire range <start,end> is mapped with type.
> *
> @@ -357,6 +373,21 @@ static unsigned long __init find_max_pfn(void)
> max_pfn = end;
> }
>
> +#ifdef CONFIG_HYPERV_GUEST
> + {
> + /*
> + * We reserve the top-most page for hypercall page. Adjust
> + * max_pfn if necessary.
> + */
> + unsigned int phys_bits = find_phys_addr_bits();
> + unsigned long hcall_pfn =
> + ((1ull << phys_bits) - 1) >> PAGE_SHIFT;
> +
> + if ( max_pfn >= hcall_pfn )
> + max_pfn = hcall_pfn - 1;
> + }
> +#endif
> +
> return max_pfn;
> }
>
> @@ -420,7 +451,7 @@ static uint64_t __init mtrr_top_of_ram(void)
> {
> uint32_t eax, ebx, ecx, edx;
> uint64_t mtrr_cap, mtrr_def, addr_mask, base, mask, top;
> - unsigned int i, phys_bits = 36;
> + unsigned int i, phys_bits;
>
> /* By default we check only Intel systems. */
> if ( e820_mtrr_clip == -1 )
> @@ -446,13 +477,7 @@ static uint64_t __init mtrr_top_of_ram(void)
> return 0;
>
> /* Find the physical address size for this CPU. */
> - eax = cpuid_eax(0x80000000);
> - if ( (eax >> 16) == 0x8000 && eax >= 0x80000008 )
> - {
> - phys_bits = (uint8_t)cpuid_eax(0x80000008);
> - if ( phys_bits > PADDR_BITS )
> - phys_bits = PADDR_BITS;
> - }
> + phys_bits = find_phys_addr_bits();
> addr_mask = ((1ull << phys_bits) - 1) & ~((1ull << 12) - 1);
>
> rdmsrl(MSR_MTRRcap, mtrr_cap);
> diff --git a/xen/arch/x86/guest/hyperv/hyperv.c
> b/xen/arch/x86/guest/hyperv/hyperv.c
> index 8d38313d7a..f986c1a805 100644
> --- a/xen/arch/x86/guest/hyperv/hyperv.c
> +++ b/xen/arch/x86/guest/hyperv/hyperv.c
> @@ -18,17 +18,27 @@
> *
> * Copyright (c) 2019 Microsoft.
> */
> +#include <xen/version.h>
> #include <xen/init.h>
>
> +#include <asm/fixmap.h>
> #include <asm/guest.h>
> #include <asm/guest/hyperv-tlfs.h>
> +#include <asm/processor.h>
>
> struct ms_hyperv_info __read_mostly ms_hyperv;
>
> -static const struct hypervisor_ops ops = {
> - .name = "Hyper-V",
> -};
> +static uint64_t generate_guest_id(void)
> +{
> + uint64_t id = 0;
> +
> + id = (uint64_t)HV_XEN_VENDOR_ID << 48;
> + id |= (xen_major_version() << 16) | xen_minor_version();
> +
> + return id;
> +}
>
> +static const struct hypervisor_ops ops;
> const struct hypervisor_ops *__init hyperv_probe(void)
> {
> uint32_t eax, ebx, ecx, edx;
> @@ -72,6 +82,43 @@ const struct hypervisor_ops *__init hyperv_probe(void)
> return &ops;
> }
>
> +static void __init setup_hypercall_page(void)
> +{
> + union hv_x64_msr_hypercall_contents hypercall_msr;
> + union hv_guest_os_id guest_id;
> + unsigned long mfn;
> +
> + rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id.raw);
> + if ( !guest_id.raw )
> + {
> + guest_id.raw = generate_guest_id();
> + wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id.raw);
> + }
> +
> + rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
> + if ( !hypercall_msr.enable )
> + {
> + mfn = ((1ull << paddr_bits) - 1) >> HV_HYP_PAGE_SHIFT;
> + hypercall_msr.enable = 1;
> + hypercall_msr.guest_physical_address = mfn;
> + wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
> + } else {
> + mfn = hypercall_msr.guest_physical_address;
> + }
> +
> + set_fixmap_x(FIX_X_HYPERV_HCALL, mfn << PAGE_SHIFT);
> +}
> +
> +static void __init setup(void)
> +{
> + setup_hypercall_page();
> +}
> +
> +static const struct hypervisor_ops ops = {
> + .name = "Hyper-V",
> + .setup = setup,
> +};
> +
> /*
> * Local variables:
> * mode: C
> diff --git a/xen/include/asm-x86/guest/hyperv-tlfs.h b/xen/include/asm-
> x86/guest/hyperv-tlfs.h
> index 05c4044976..5d37efd2d2 100644
> --- a/xen/include/asm-x86/guest/hyperv-tlfs.h
> +++ b/xen/include/asm-x86/guest/hyperv-tlfs.h
> @@ -318,15 +318,16 @@ struct ms_hyperv_tsc_page {
> *
> * Bit(s)
> * 63 - Indicates if the OS is Open Source or not; 1 is Open Source
> - * 62:56 - Os Type; Linux is 0x100
> + * 62:56 - Os Type; Linux 0x100, FreeBSD 0x200, Xen 0x300
This comment isn't quite right -- it reflects the mistake in the
TLFS that is being corrected. The field 62:56 is only 7 bits wide,
so 0x100, 0x200, etc. won't fit. The actual values are: Linux 0x1,
FreeBSD 0x2, and Xen 0x3. Then bits 55:48 are 0x00.
> * 55:48 - Distro specific identification
> - * 47:16 - Linux kernel version number
> + * 47:16 - Guest OS version number
> * 15:0 - Distro specific identification
> *
> *
> */
>
> #define HV_LINUX_VENDOR_ID 0x8100
> +#define HV_XEN_VENDOR_ID 0x8300
> union hv_guest_os_id
> {
> uint64_t raw;
> --
> 2.20.1
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