From 039576c03c35e2f990ad9bb9c39e1bad3cd60d34 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 20 Mar 2007 12:46:50 +0200 Subject: KVM: Avoid guest virtual addresses in string pio userspace interface The current string pio interface communicates using guest virtual addresses, relying on userspace to translate addresses and to check permissions. This interface cannot fully support guest smp, as the check needs to take into account two pages at one in case an unaligned string transfer straddles a page boundary. Change the interface not to communicate guest addresses at all; instead use a buffer page (mmaped by userspace) and do transfers there. The kernel manages the virtual to physical translation and can perform the checks atomically by taking the appropriate locks. Signed-off-by: Avi Kivity --- drivers/kvm/svm.c | 40 +++++++++++++++++++--------------------- 1 file changed, 19 insertions(+), 21 deletions(-) (limited to 'drivers/kvm/svm.c') diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c index 2396ada..64afc5c 100644 --- a/drivers/kvm/svm.c +++ b/drivers/kvm/svm.c @@ -984,7 +984,7 @@ static int io_get_override(struct kvm_vcpu *vcpu, return 0; } -static unsigned long io_adress(struct kvm_vcpu *vcpu, int ins, u64 *address) +static unsigned long io_adress(struct kvm_vcpu *vcpu, int ins, gva_t *address) { unsigned long addr_mask; unsigned long *reg; @@ -1028,40 +1028,38 @@ static unsigned long io_adress(struct kvm_vcpu *vcpu, int ins, u64 *address) static int io_interception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) { u32 io_info = vcpu->svm->vmcb->control.exit_info_1; //address size bug? - int _in = io_info & SVM_IOIO_TYPE_MASK; + int size, down, in, string, rep; + unsigned port; + unsigned long count; + gva_t address = 0; ++kvm_stat.io_exits; vcpu->svm->next_rip = vcpu->svm->vmcb->control.exit_info_2; - kvm_run->exit_reason = KVM_EXIT_IO; - kvm_run->io.port = io_info >> 16; - kvm_run->io.direction = (_in) ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT; - kvm_run->io.size = ((io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT); - kvm_run->io.string = (io_info & SVM_IOIO_STR_MASK) != 0; - kvm_run->io.rep = (io_info & SVM_IOIO_REP_MASK) != 0; - kvm_run->io.count = 1; + in = (io_info & SVM_IOIO_TYPE_MASK) != 0; + port = io_info >> 16; + size = (io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT; + string = (io_info & SVM_IOIO_STR_MASK) != 0; + rep = (io_info & SVM_IOIO_REP_MASK) != 0; + count = 1; + down = (vcpu->svm->vmcb->save.rflags & X86_EFLAGS_DF) != 0; - if (kvm_run->io.string) { + if (string) { unsigned addr_mask; - addr_mask = io_adress(vcpu, _in, &kvm_run->io.address); + addr_mask = io_adress(vcpu, in, &address); if (!addr_mask) { printk(KERN_DEBUG "%s: get io address failed\n", __FUNCTION__); return 1; } - if (kvm_run->io.rep) { - kvm_run->io.count - = vcpu->regs[VCPU_REGS_RCX] & addr_mask; - kvm_run->io.string_down = (vcpu->svm->vmcb->save.rflags - & X86_EFLAGS_DF) != 0; - } - } else - kvm_run->io.value = vcpu->svm->vmcb->save.rax; - vcpu->pio_pending = 1; - return 0; + if (rep) + count = vcpu->regs[VCPU_REGS_RCX] & addr_mask; + } + return kvm_setup_pio(vcpu, kvm_run, in, size, count, string, down, + address, rep, port); } static int nop_on_interception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) -- cgit v1.1