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Subject[PATCH 6/7] KVM: Don't require explicit indication of completion of mmio or pio
Date
It is illegal not to return from a pio or mmio request without completing
it, as mmio or pio is an atomic operation. Therefore, we can simplify
the userspace interface by avoiding the completion indication.

Signed-off-by: Avi Kivity <avi@qumranet.com>
---
drivers/kvm/kvm_main.c | 28 +++++++++++++---------------
include/linux/kvm.h | 5 ++---
2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index a9ba42f..4c5b8db 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1237,8 +1237,10 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
kvm_arch_ops->decache_regs(vcpu);
kvm_arch_ops->set_rflags(vcpu, emulate_ctxt.eflags);

- if (vcpu->mmio_is_write)
+ if (vcpu->mmio_is_write) {
+ vcpu->mmio_needed = 0;
return EMULATE_DO_MMIO;
+ }

return EMULATE_DONE;
}
@@ -1692,8 +1694,6 @@ static int complete_pio(struct kvm_vcpu *vcpu)
vcpu->regs[VCPU_REGS_RSI] += delta;
}

- vcpu->run->io_completed = 0;
-
kvm_arch_ops->decache_regs(vcpu);

io->count -= io->cur_count;
@@ -1800,20 +1800,18 @@ static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
/* re-sync apic's tpr */
vcpu->cr8 = kvm_run->cr8;

- if (kvm_run->io_completed) {
- if (vcpu->pio.cur_count) {
- r = complete_pio(vcpu);
- if (r)
- goto out;
- } else if (!vcpu->mmio_is_write) {
- memcpy(vcpu->mmio_data, kvm_run->mmio.data, 8);
- vcpu->mmio_read_completed = 1;
- emulate_instruction(vcpu, kvm_run,
- vcpu->mmio_fault_cr2, 0);
- }
+ if (vcpu->pio.cur_count) {
+ r = complete_pio(vcpu);
+ if (r)
+ goto out;
}

- vcpu->mmio_needed = 0;
+ if (vcpu->mmio_needed) {
+ memcpy(vcpu->mmio_data, kvm_run->mmio.data, 8);
+ vcpu->mmio_read_completed = 1;
+ emulate_instruction(vcpu, kvm_run, vcpu->mmio_fault_cr2, 0);
+ vcpu->mmio_needed = 0;
+ }

if (kvm_run->exit_reason == KVM_EXIT_HYPERCALL) {
kvm_arch_ops->cache_regs(vcpu);
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 07bf353..738c2f5 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -11,7 +11,7 @@
#include <asm/types.h>
#include <linux/ioctl.h>

-#define KVM_API_VERSION 10
+#define KVM_API_VERSION 11

/*
* Architectural interrupt line count, and the size of the bitmap needed
@@ -58,9 +58,8 @@ enum kvm_exit_reason {
/* for KVM_RUN, returned by mmap(vcpu_fd, offset=0) */
struct kvm_run {
/* in */
- __u32 io_completed; /* mmio/pio request completed */
__u8 request_interrupt_window;
- __u8 padding1[3];
+ __u8 padding1[7];

/* out */
__u32 exit_reason;
--
1.5.0.6
-
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