On Wed, 2021-10-13 at 12:56 -0400, Paolo Bonzini wrote:
emulator_pio_in handles both the case where the data is pending in vcpu->arch.pio.count, and the case where I/O has to be done via either an in-kernel device or a userspace exit. For SEV-ES we would like to split these, to identify clearly the moment at which the sev_pio_data is consumed. To this end, create two different functions: __emulator_pio_in fills in vcpu->arch.pio.count, while complete_emulator_pio_in clears it and releases vcpu->arch.pio.data.
While at it, remove the void* argument also from emulator_pio_in_out.
s/remove the void* argument/remove the unused 'void* val' argument/ maybe?
No functional change intended.
Cc: stable@vger.kernel.org Fixes: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest") Signed-off-by: Paolo Bonzini pbonzini@redhat.com
arch/x86/kvm/x86.c | 42 +++++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 19 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8880dc36a2b4..07d9533b471d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6906,7 +6906,7 @@ static int kernel_pio(struct kvm_vcpu *vcpu, void *pd) } static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
unsigned short port, void *val,
unsigned short port, unsigned int count, bool in){ vcpu->arch.pio.port = port; @@ -6927,26 +6927,31 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size, return 0; } -static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
unsigned short port, void *val, unsigned int count)+static int __emulator_pio_in(struct kvm_vcpu *vcpu, int size,
unsigned short port, unsigned int count){
- int ret;
- if (vcpu->arch.pio.count)
goto data_avail;
- WARN_ON(vcpu->arch.pio.count); memset(vcpu->arch.pio_data, 0, size * count);
- return emulator_pio_in_out(vcpu, size, port, count, true);
+}
- ret = emulator_pio_in_out(vcpu, size, port, val, count, true);
- if (ret) {
-data_avail:
memcpy(val, vcpu->arch.pio_data, size * count);trace_kvm_pio(KVM_PIO_IN, port, size, count, vcpu->arch.pio_data);vcpu->arch.pio.count = 0;return 1;- }
+static void complete_emulator_pio_in(struct kvm_vcpu *vcpu, int size,
unsigned short port, void *val)+{
- memcpy(val, vcpu->arch.pio_data, size * vcpu->arch.pio.count);
- trace_kvm_pio(KVM_PIO_IN, port, size, vcpu->arch.pio.count, vcpu->arch.pio_data);
- vcpu->arch.pio.count = 0;
+}
- return 0;
+static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
unsigned short port, void *val, unsigned int count)+{
- if (!vcpu->arch.pio.count && !__emulator_pio_in(vcpu, size, port, count))
return 0;
^^ maybe I would add a comment here about the fact that kernel completed the emulation when returing here.
- WARN_ON(count != vcpu->arch.pio.count);
- complete_emulator_pio_in(vcpu, size, port, val);
- return 1;
} static int emulator_pio_in_emulated(struct x86_emulate_ctxt *ctxt, @@ -6965,12 +6970,11 @@ static int emulator_pio_out(struct kvm_vcpu *vcpu, int size, memcpy(vcpu->arch.pio_data, val, size * count); trace_kvm_pio(KVM_PIO_OUT, port, size, count, vcpu->arch.pio_data);
- ret = emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
- ret = emulator_pio_in_out(vcpu, size, port, count, false); if (ret) vcpu->arch.pio.count = 0;
return ret;
} static int emulator_pio_out_emulated(struct x86_emulate_ctxt *ctxt,
Reviewed-by: Maxim Levitsky mlevitsk@redhat.com
Best regards, Maxim Levitsky