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KVM: x86: split the two parts of emulator_pio_in
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.
Because this patch has to be backported, things are left a bit messy.
kernel_pio() operates on vcpu->arch.pio, which leads to emulator_pio_in()
having with two calls to complete_emulator_pio_in(). It will be fixed
in the next release.
While at it, remove the unused void* val argument of emulator_pio_in_out.
The function currently hardcodes vcpu->arch.pio_data as the
source/destination buffer, which sucks but will be fixed after the more
severe SEV-ES buffer overflow.
No functional change intended.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e
("KVM: SVM: Support string IO operations for an SEV-ES guest")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
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@ -6906,7 +6906,7 @@ static int kernel_pio(struct kvm_vcpu *vcpu, void *pd)
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}
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static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
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unsigned short port, void *val,
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unsigned short port,
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unsigned int count, bool in)
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{
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vcpu->arch.pio.port = port;
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@ -6927,26 +6927,38 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
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return 0;
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}
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static int __emulator_pio_in(struct kvm_vcpu *vcpu, int size,
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unsigned short port, unsigned int count)
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{
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WARN_ON(vcpu->arch.pio.count);
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memset(vcpu->arch.pio_data, 0, size * count);
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return emulator_pio_in_out(vcpu, size, port, count, true);
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}
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static void complete_emulator_pio_in(struct kvm_vcpu *vcpu, int size,
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unsigned short port, void *val)
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{
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memcpy(val, vcpu->arch.pio_data, size * vcpu->arch.pio.count);
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trace_kvm_pio(KVM_PIO_IN, port, size, vcpu->arch.pio.count, vcpu->arch.pio_data);
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vcpu->arch.pio.count = 0;
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}
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static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
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unsigned short port, void *val, unsigned int count)
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{
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int ret;
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if (vcpu->arch.pio.count) {
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/* Complete previous iteration. */
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} else {
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int r = __emulator_pio_in(vcpu, size, port, count);
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if (!r)
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return r;
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if (vcpu->arch.pio.count)
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goto data_avail;
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memset(vcpu->arch.pio_data, 0, size * count);
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ret = emulator_pio_in_out(vcpu, size, port, val, count, true);
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if (ret) {
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data_avail:
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memcpy(val, vcpu->arch.pio_data, size * count);
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trace_kvm_pio(KVM_PIO_IN, port, size, count, vcpu->arch.pio_data);
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vcpu->arch.pio.count = 0;
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return 1;
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/* Results already available, fall through. */
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}
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return 0;
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WARN_ON(count != vcpu->arch.pio.count);
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complete_emulator_pio_in(vcpu, size, port, val);
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return 1;
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}
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static int emulator_pio_in_emulated(struct x86_emulate_ctxt *ctxt,
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@ -6965,12 +6977,11 @@ static int emulator_pio_out(struct kvm_vcpu *vcpu, int size,
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memcpy(vcpu->arch.pio_data, val, size * count);
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trace_kvm_pio(KVM_PIO_OUT, port, size, count, vcpu->arch.pio_data);
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ret = emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
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ret = emulator_pio_in_out(vcpu, size, port, count, false);
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if (ret)
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vcpu->arch.pio.count = 0;
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return ret;
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}
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static int emulator_pio_out_emulated(struct x86_emulate_ctxt *ctxt,
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