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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-02-18 15:29:50 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-03-16 17:57:53 +0100 |
| commit | 06add254c7f3b7f6fdfe04eb028aaabe5b27a734 (patch) | |
| tree | f5ef8f264e875f296c534f56ca7793f8a1abfbe3 /arch | |
| parent | 2f728d66e8a7d89d7cb141bf0acb30c61ae7ded5 (diff) | |
| download | lwn-06add254c7f3b7f6fdfe04eb028aaabe5b27a734.tar.gz lwn-06add254c7f3b7f6fdfe04eb028aaabe5b27a734.zip | |
KVM: x86: Shrink the usercopy region of the emulation context
Shuffle a few operand structs to the end of struct x86_emulate_ctxt and
update the cache creation to whitelist only the region of the emulation
context that is expected to be copied to/from user memory, e.g. the
instruction operands, registers, and fetch/io/mem caches.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/kvm_emulate.h | 8 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 12 |
2 files changed, 11 insertions, 9 deletions
diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index 3a66f80d7d00..f86fe6bf170d 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -334,9 +334,6 @@ struct x86_emulate_ctxt { u8 intercept; u8 op_bytes; u8 ad_bytes; - struct operand src; - struct operand src2; - struct operand dst; union { int (*execute)(struct x86_emulate_ctxt *ctxt); fastop_t fop; @@ -364,6 +361,11 @@ struct x86_emulate_ctxt { u8 seg_override; u64 d; unsigned long _eip; + + /* Here begins the usercopy section. */ + struct operand src; + struct operand src2; + struct operand dst; struct operand memop; /* Fields above regs are cleared together. */ unsigned long _regs[NR_VCPU_REGS]; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f55899055467..a69f7bf020d9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -235,13 +235,13 @@ static struct kmem_cache *x86_emulator_cache; static struct kmem_cache *kvm_alloc_emulator_cache(void) { - return kmem_cache_create_usercopy("x86_emulator", - sizeof(struct x86_emulate_ctxt), + unsigned int useroffset = offsetof(struct x86_emulate_ctxt, src); + unsigned int size = sizeof(struct x86_emulate_ctxt); + + return kmem_cache_create_usercopy("x86_emulator", size, __alignof__(struct x86_emulate_ctxt), - SLAB_ACCOUNT, - 0, - sizeof(struct x86_emulate_ctxt), - NULL); + SLAB_ACCOUNT, useroffset, + size - useroffset, NULL); } static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt); |