From 36d546d59af7cfc984b159016bed3e2a3113266f Mon Sep 17 00:00:00 2001 From: Hou Wenlong Date: Fri, 2 Sep 2022 10:47:00 +0800 Subject: KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed The return value of emulator_{get|set}_mst_with_filter() is confused, since msr access error and emulator error are mixed. Although, KVM_MSR_RET_* doesn't conflict with X86EMUL_IO_NEEDED at present, it is better to convert msr access error to emulator error if error value is needed. So move "r < 0" handling for wrmsr emulation into the set helper function, then only X86EMUL_* is returned in the helper functions. Also add "r < 0" check in the get helper function, although KVM doesn't return -errno today, but assuming that will always hold true is unnecessarily risking. Suggested-by: Sean Christopherson Signed-off-by: Hou Wenlong Link: https://lore.kernel.org/r/09b2847fc3bcb8937fb11738f0ccf7be7f61d9dd.1661930557.git.houwenlong.hwl@antgroup.com [sean: wrap changelog less aggressively] Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) (limited to 'arch/x86/kvm/emulate.c') diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 9367aaaacdf9..862498dc3d75 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3647,13 +3647,10 @@ static int em_wrmsr(struct x86_emulate_ctxt *ctxt) | ((u64)reg_read(ctxt, VCPU_REGS_RDX) << 32); r = ctxt->ops->set_msr_with_filter(ctxt, msr_index, msr_data); - if (r == X86EMUL_IO_NEEDED) - return r; - - if (r > 0) + if (r == X86EMUL_PROPAGATE_FAULT) return emulate_gp(ctxt, 0); - return r < 0 ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; + return r; } static int em_rdmsr(struct x86_emulate_ctxt *ctxt) @@ -3664,15 +3661,14 @@ static int em_rdmsr(struct x86_emulate_ctxt *ctxt) r = ctxt->ops->get_msr_with_filter(ctxt, msr_index, &msr_data); - if (r == X86EMUL_IO_NEEDED) - return r; - - if (r) + if (r == X86EMUL_PROPAGATE_FAULT) return emulate_gp(ctxt, 0); - *reg_write(ctxt, VCPU_REGS_RAX) = (u32)msr_data; - *reg_write(ctxt, VCPU_REGS_RDX) = msr_data >> 32; - return X86EMUL_CONTINUE; + if (r == X86EMUL_CONTINUE) { + *reg_write(ctxt, VCPU_REGS_RAX) = (u32)msr_data; + *reg_write(ctxt, VCPU_REGS_RDX) = msr_data >> 32; + } + return r; } static int em_store_sreg(struct x86_emulate_ctxt *ctxt, int segment) -- cgit