The caller of kernel_pio already has arguments for most of what kernel_pio
fishes out of vcpu->arch.pio. This is the first step towards ensuring that
vcpu->arch.pio.* is only used when exiting to userspace.
We can now also WARN if emulated PIO performs successful in-kernel iterations
before having to fall back to userspace. The code is not ready for that, and
it should never happen.
No functional change intended.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 39 +++++++++++++++++----------------------
1 file changed, 17 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 79efdc19b4c8..2f9100f2564e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7415,37 +7415,32 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
return emulator_write_emulated(ctxt, addr, new, bytes, exception);
}
-static int kernel_pio(struct kvm_vcpu *vcpu, void *pd)
-{
- int r = 0, i;
-
- for (i = 0; i < vcpu->arch.pio.count; i++) {
- if (vcpu->arch.pio.in)
- r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, vcpu->arch.pio.port,
- vcpu->arch.pio.size, pd);
- else
- r = kvm_io_bus_write(vcpu, KVM_PIO_BUS,
- vcpu->arch.pio.port, vcpu->arch.pio.size,
- pd);
- if (r)
- break;
- pd += vcpu->arch.pio.size;
- }
- return r;
-}
-
static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
unsigned short port,
unsigned int count, bool in)
{
+ void *data = vcpu->arch.pio_data;
+ unsigned i;
+ int r;
+
vcpu->arch.pio.port = port;
vcpu->arch.pio.in = in;
- vcpu->arch.pio.count = count;
+ vcpu->arch.pio.count = count;
vcpu->arch.pio.size = size;
- if (!kernel_pio(vcpu, vcpu->arch.pio_data))
- return 1;
+ for (i = 0; i < count; i++) {
+ if (in)
+ r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, port, size, data);
+ else
+ r = kvm_io_bus_write(vcpu, KVM_PIO_BUS, port, size, data);
+ if (r)
+ goto userspace_io;
+ data += size;
+ }
+ return 1;
+userspace_io:
+ WARN_ON(i != 0);
vcpu->run->exit_reason = KVM_EXIT_IO;
vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
vcpu->run->io.size = size;
--
2.31.1
