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authorPaolo Bonzini <pbonzini@redhat.com>2021-10-13 12:32:02 -0400
committerPaolo Bonzini <pbonzini@redhat.com>2021-10-22 10:08:00 -0400
commit3b27de27183911d461afedf50c6fa30c59740c07 (patch)
treee349f18239bb64704fc1fa3bc54edcff20deeac6
parentea724ea420aac58b41bc822d1aed6940b136b78d (diff)
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: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/x86.c45
1 files changed, 28 insertions, 17 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 78ed0fe9fa1e..c51ea81019e3 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 +6927,38 @@ 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;
+ WARN_ON(vcpu->arch.pio.count);
+ memset(vcpu->arch.pio_data, 0, size * count);
+ return emulator_pio_in_out(vcpu, size, port, count, true);
+}
- if (vcpu->arch.pio.count)
- goto data_avail;
+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;
+}
- memset(vcpu->arch.pio_data, 0, size * count);
+static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
+ unsigned short port, void *val, unsigned int count)
+{
+ if (vcpu->arch.pio.count) {
+ /* Complete previous iteration. */
+ } else {
+ int r = __emulator_pio_in(vcpu, size, port, count);
+ if (!r)
+ return r;
- 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;
+ /* Results already available, fall through. */
}
- return 0;
+ 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 +6977,11 @@ 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,