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KVM: Don't require explicit indication of completion of mmio or pio

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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>
This commit is contained in:
Avi Kivity 2007-04-29 15:02:17 +03:00
parent e7df56e4a0
commit 02c8320972
2 changed files with 24 additions and 25 deletions
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44
drivers/kvm/kvm_main.c
View file

@ -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;
@ -1800,25 +1800,25 @@ 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;
vcpu->mmio_needed = 0;
r = emulate_instruction(vcpu, kvm_run,
vcpu->mmio_fault_cr2, 0);
if (r == EMULATE_DO_MMIO) {
/*
* Read-modify-write. Back to userspace.
*/
kvm_run->exit_reason = KVM_EXIT_MMIO;
r = 0;
goto out;
}
if (vcpu->pio.cur_count) {
r = complete_pio(vcpu);
if (r)
goto out;
}
if (vcpu->mmio_needed) {
memcpy(vcpu->mmio_data, kvm_run->mmio.data, 8);
vcpu->mmio_read_completed = 1;
vcpu->mmio_needed = 0;
r = emulate_instruction(vcpu, kvm_run,
vcpu->mmio_fault_cr2, 0);
if (r == EMULATE_DO_MMIO) {
/*
* Read-modify-write. Back to userspace.
*/
kvm_run->exit_reason = KVM_EXIT_MMIO;
r = 0;
goto out;
}
}

5
include/linux/kvm.h
View file

@ -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;