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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-11-11 23:03:18 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-11-16 11:24:00 +0100 |
| commit | 6b546e1c9ad2a25f874f8bc6077d0f55f9446414 (patch) | |
| tree | 86a938e9727f3cc7e5a8c8a135de3d70bc04b78d /arch/x86/mm | |
| parent | 505b789996f64bdbfcc5847dd4b5076fc7c50274 (diff) | |
| download | linux-6b546e1c9ad2a25f874f8bc6077d0f55f9446414.tar.bz2 | |
x86/tss: Fix and move VMX BUILD_BUG_ON()
The BUILD_BUG_ON(IO_BITMAP_OFFSET - 1 == 0x67) in the VMX code is bogus in
two aspects:
1) This wants to be in generic x86 code simply to catch issues even when
VMX is disabled in Kconfig.
2) The IO_BITMAP_OFFSET is not the right thing to check because it makes
asssumptions about the layout of tss_struct. Nothing requires that the
I/O bitmap is placed right after x86_tss, which is the hardware mandated
tss structure. It pointlessly makes restrictions on the struct
tss_struct layout.
The proper thing to check is:
- Offset of x86_tss in tss_struct is 0
- Size of x86_tss == 0x68
Move it to the other build time TSS checks and make it do the right thing.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/cpu_entry_area.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index 752ad11d6868..2c1d4223a343 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -161,6 +161,14 @@ static void __init setup_cpu_entry_area(unsigned int cpu) BUILD_BUG_ON((offsetof(struct tss_struct, x86_tss) ^ offsetofend(struct tss_struct, x86_tss)) & PAGE_MASK); BUILD_BUG_ON(sizeof(struct tss_struct) % PAGE_SIZE != 0); + /* + * VMX changes the host TR limit to 0x67 after a VM exit. This is + * okay, since 0x67 covers the size of struct x86_hw_tss. Make sure + * that this is correct. + */ + BUILD_BUG_ON(offsetof(struct tss_struct, x86_tss) != 0); + BUILD_BUG_ON(sizeof(struct x86_hw_tss) != 0x68); + cea_map_percpu_pages(&cea->tss, &per_cpu(cpu_tss_rw, cpu), sizeof(struct tss_struct) / PAGE_SIZE, tss_prot); |