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authorThomas Gleixner <tglx@linutronix.de>2019-11-12 01:03:18 +0300
committerThomas Gleixner <tglx@linutronix.de>2019-11-16 13:24:00 +0300
commit6b546e1c9ad2a25f874f8bc6077d0f55f9446414 (patch)
tree86a938e9727f3cc7e5a8c8a135de3d70bc04b78d /arch/x86/mm/cpu_entry_area.c
parent505b789996f64bdbfcc5847dd4b5076fc7c50274 (diff)
downloadlinux-6b546e1c9ad2a25f874f8bc6077d0f55f9446414.tar.xz
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/cpu_entry_area.c')
-rw-r--r--arch/x86/mm/cpu_entry_area.c8
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);