x86/jailhouse: Improve setup data version comparison

Soon, setup_data will contain information on passed-through platform
UARTs. This requires some preparational work for the sanity check of the
header and the check of the version.

Use the following strategy:

  1. Ensure that the header declares at least enough space for the
     version and the compatible_version as it must hold that fields for
     any version. The location and semantics of header+version fields
     will never change.

  2. Copy over data -- as much as as possible. The length is either
     limited by the header length or the length of setup_data.

  3. Things are now in place -- sanity check if the header length
     complies the actual version.

For future versions of the setup_data, only step 3 requires alignment.

Signed-off-by: Ralf Ramsauer <ralf.ramsauer@oth-regensburg.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: jailhouse-dev@googlegroups.com
Cc: Juergen Gross <jgross@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191010102102.421035-2-ralf.ramsauer@oth-regensburg.de
This commit is contained in:
Ralf Ramsauer
2019-10-10 12:21:01 +02:00
committed by Borislav Petkov
parent 4fb7d08707
commit 0935e5f752
2 changed files with 45 additions and 28 deletions

View File

@@ -139,15 +139,19 @@ struct boot_e820_entry {
* setup data structure.
*/
struct jailhouse_setup_data {
__u16 version;
__u16 compatible_version;
__u16 pm_timer_address;
__u16 num_cpus;
__u64 pci_mmconfig_base;
__u32 tsc_khz;
__u32 apic_khz;
__u8 standard_ioapic;
__u8 cpu_ids[255];
struct {
__u16 version;
__u16 compatible_version;
} __attribute__((packed)) hdr;
struct {
__u16 pm_timer_address;
__u16 num_cpus;
__u64 pci_mmconfig_base;
__u32 tsc_khz;
__u32 apic_khz;
__u8 standard_ioapic;
__u8 cpu_ids[255];
} __attribute__((packed)) v1;
} __attribute__((packed));
/* The so-called "zeropage" */