Messages in this thread Patch in this message | | | From | Maxim Levitsky <> | Subject | [PATCH v3 06/13] KVM: x86: emulator/smm: number of GPRs in the SMRAM image depends on the image format | Date | Wed, 3 Aug 2022 18:50:04 +0300 |
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On 64 bit host, if the guest doesn't have X86_FEATURE_LM, KVM will access 16 gprs to 32-bit smram image, causing out-ouf-bound ram access.
On 32 bit host, the rsm_load_state_64/enter_smm_save_state_64 is compiled out, thus access overflow can't happen.
Fixes: b443183a25ab61 ("KVM: x86: Reduce the number of emulator GPRs to '8' for 32-bit KVM")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/emulate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 765ec65b2861ba..18551611cb13af 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2473,7 +2473,7 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, ctxt->eflags = GET_SMSTATE(u32, smstate, 0x7ff4) | X86_EFLAGS_FIXED; ctxt->_eip = GET_SMSTATE(u32, smstate, 0x7ff0); - for (i = 0; i < NR_EMULATOR_GPRS; i++) + for (i = 0; i < 8; i++) *reg_write(ctxt, i) = GET_SMSTATE(u32, smstate, 0x7fd0 + i * 4); val = GET_SMSTATE(u32, smstate, 0x7fcc); @@ -2530,7 +2530,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u16 selector; int i, r; - for (i = 0; i < NR_EMULATOR_GPRS; i++) + for (i = 0; i < 16; i++) *reg_write(ctxt, i) = GET_SMSTATE(u64, smstate, 0x7ff8 - i * 8); ctxt->_eip = GET_SMSTATE(u64, smstate, 0x7f78); -- 2.26.3
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