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KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed

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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 <seanjc@google.com>
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Link: https://lore.kernel.org/r/09b2847fc3bcb8937fb11738f0ccf7be7f61d9dd.1661930557.git.houwenlong.hwl@antgroup.com
[sean: wrap changelog less aggressively]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Hou Wenlong 2022-09-02 10:47:00 +08:00 committed by Paolo Bonzini
parent b85a97b851
commit 36d546d59a
2 changed files with 24 additions and 22 deletions
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20
arch/x86/kvm/emulate.c
View File

@ -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)

26
arch/x86/kvm/x86.c
View File

@ -7920,14 +7920,17 @@ static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
int r;
r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
if (r < 0)
return X86EMUL_UNHANDLEABLE;
if (r && kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
complete_emulated_rdmsr, r)) {
/* Bounce to user space */
return X86EMUL_IO_NEEDED;
if (r) {
if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
complete_emulated_rdmsr, r))
return X86EMUL_IO_NEEDED;
return X86EMUL_PROPAGATE_FAULT;
}
return r;
return X86EMUL_CONTINUE;
}
static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
@ -7937,14 +7940,17 @@ static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
int r;
r = kvm_set_msr_with_filter(vcpu, msr_index, data);
if (r < 0)
return X86EMUL_UNHANDLEABLE;
if (r && kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
complete_emulated_msr_access, r)) {
/* Bounce to user space */
return X86EMUL_IO_NEEDED;
if (r) {
if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
complete_emulated_msr_access, r))
return X86EMUL_IO_NEEDED;
return X86EMUL_PROPAGATE_FAULT;
}
return r;
return X86EMUL_CONTINUE;
}
static int emulator_get_msr(struct x86_emulate_ctxt *ctxt,