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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 1/4] x86/PVHv2: Add memory map pointer to hvm_start_info struct
On Thu, Mar 15, 2018 at 02:33:09PM -0700, Maran Wilson wrote:
> The start info structure that is defined as part of the x86/HVM direct boot
> ABI and used for starting Xen PVH guests would be more versatile if it also
> included a way to pass information about the memory map to the guest. This
> would allow KVM guests to share the same entry point.
>
> Signed-off-by: Maran Wilson <maran.wilson@xxxxxxxxxx>
> ---
> xen/include/public/arch-x86/hvm/start_info.h | 66
> +++++++++++++++++++++++++++-
> 1 file changed, 65 insertions(+), 1 deletion(-)
>
> diff --git a/xen/include/public/arch-x86/hvm/start_info.h
> b/xen/include/public/arch-x86/hvm/start_info.h
> index 6484159..f2e8ba6 100644
> --- a/xen/include/public/arch-x86/hvm/start_info.h
> +++ b/xen/include/public/arch-x86/hvm/start_info.h
> @@ -33,8 +33,9 @@
> * | magic | Contains the magic value XEN_HVM_START_MAGIC_VALUE
> * | | ("xEn3" with the 0x80 bit of the "E" set).
> * 4 +----------------+
> - * | version | Version of this structure. Current version is 0. New
> + * | version | Version of this structure. Current version is 1. New
> * | | versions are guaranteed to be backwards-compatible.
> + * | | For PV guests only 0 allowed, for PVH 0 or 1
> allowed.
Why are you adding the above sentence? PV guest never used or will use
the hvm_start_info structure (note the hvm_ prefix).
> * 8 +----------------+
> * | flags | SIF_xxx flags.
> * 12 +----------------+
> @@ -48,6 +49,15 @@
> * 32 +----------------+
> * | rsdp_paddr | Physical address of the RSDP ACPI data structure.
> * 40 +----------------+
> + * | memmap_paddr | Physical address of the (optional) memory map. Only
> + * | | present in version 1 and newer of the structure.
> + * 48 +----------------+
> + * | memmap_entries | Number of entries in the memory map table. Zero
> + * | | if there is no memory map being provided. Only
Again (as I've mentioned in previous reviews) the way to signal a
non-present memory map is to set memmap_paddr to 0, not memmap_entries
to 0. This is already covered by the comment at the top of the header,
which states:
NOTE: nothing will be loaded at physical address 0, so a 0 value in any
of the address fields should be treated as not present.
> + * | | present in version 1 and newer of the structure.
> + * 52 +----------------+
> + * | reserved | Version 1 and newer only.
> + * 56 +----------------+
> *
> * The layout of each entry in the module structure is the following:
> *
> @@ -62,14 +72,53 @@
> * | reserved |
> * 32 +----------------+
> *
> + * The layout of each entry in the memory map table is as follows:
> + *
> + * 0 +----------------+
> + * | addr | Base address
> + * 8 +----------------+
> + * | size | Size of mapping in bytes
> + * 16 +----------------+
> + * | type | Type of mapping as defined between the hypervisor
> + * | | and guest it's starting. See XEN_HVM_MEMMAP_TYPE_*
> + * | | values below.
> + * 20 +----------------|
> + * | reserved |
> + * 24 +----------------+
> + *
> * The address and sizes are always a 64bit little endian unsigned integer.
> *
> * NB: Xen on x86 will always try to place all the data below the 4GiB
> * boundary.
> + *
> + * Version numbers of the hvm_start_info structure have evolved like this:
> + *
> + * Version 0: Initial implementation.
> + *
> + * Version 1: Added the memmap_paddr/memmap_entries fields (plus 4 bytes of
> + * padding) to the end of the hvm_start_info struct. These new
> + * fields can be used to pass a memory map to the guest. The
> + * memory map is optional and so guests that understand version 1
> + * of the structure must check that memmap_entries is non-zero
> + * before trying to read the memory map.
Same again, the guest will have to check memmap_paddr != 0, not
memmap_entries, like it's done for other fields that contain a
physical address.
> */
> #define XEN_HVM_START_MAGIC_VALUE 0x336ec578
>
> /*
> + * The values used in the type field of the memory map table entries are
> + * defined below and match the Address Range Types as defined in the "System
> + * Address Map Interfaces" section of the ACPI Specification. Please refer to
> + * section 15 in version 6.2 of the ACPI spec: http://uefi.org/specifications
> + */
> +#define XEN_HVM_MEMMAP_TYPE_RAM 1
> +#define XEN_HVM_MEMMAP_TYPE_RESERVED 2
> +#define XEN_HVM_MEMMAP_TYPE_ACPI 3
> +#define XEN_HVM_MEMMAP_TYPE_NVS 4
> +#define XEN_HVM_MEMMAP_TYPE_UNUSABLE 5
> +#define XEN_HVM_MEMMAP_TYPE_DISABLED 6
> +#define XEN_HVM_MEMMAP_TYPE_PMEM 7
> +
> +/*
> * C representation of the x86/HVM start info layout.
> *
> * The canonical definition of this layout is above, this is just a way to
> @@ -86,6 +135,14 @@ struct hvm_start_info {
> uint64_t cmdline_paddr; /* Physical address of the command line.
> */
> uint64_t rsdp_paddr; /* Physical address of the RSDP ACPI data
> */
> /* structure.
> */
> + uint64_t memmap_paddr; /* Physical address of an array of */
> + /* hvm_memmap_table_entry. Only present in */
> + /* version 1 and newer of the structure */
> + uint32_t memmap_entries; /* Number of entries in the memmap table. */
> + /* Only present in version 1 and newer of */
> + /* the structure. Value will be zero if */
> + /* there is no memory map being provided. */
> + uint32_t reserved; /* Must be zero for Version 1.
> */
As mentioned in previous reviews: no tabs please.
> };
>
> struct hvm_modlist_entry {
> @@ -95,4 +152,11 @@ struct hvm_modlist_entry {
> uint64_t reserved;
> };
>
> +struct hvm_memmap_table_entry {
> + uint64_t addr; /* Base address of the memory region */
> + uint64_t size; /* Size of the memory region in bytes */
> + uint32_t type; /* Mapping type */
> + uint32_t reserved; /* Must be zero for Version 1.
> */
> +};
No tabs please.
Thanks, Roger.
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