From 908a7bdd6adba3dfd35d8a74a48aed90593de178 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 18 Feb 2013 11:21:16 +0100 Subject: [PATCH] KVM: nVMX: Improve I/O exit handling This prevents trapping L2 I/O exits if L1 has neither unconditional nor bitmap-based exiting enabled. Furthermore, it implements I/O bitmap handling. Reviewed-by: Gleb Natapov Signed-off-by: Jan Kiszka Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/vmx.c | 49 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 47 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 6667042714cc..b4ce43c82748 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5908,6 +5908,52 @@ static int (*const kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = { static const int kvm_vmx_max_exit_handlers = ARRAY_SIZE(kvm_vmx_exit_handlers); +static bool nested_vmx_exit_handled_io(struct kvm_vcpu *vcpu, + struct vmcs12 *vmcs12) +{ + unsigned long exit_qualification; + gpa_t bitmap, last_bitmap; + unsigned int port; + int size; + u8 b; + + if (nested_cpu_has(vmcs12, CPU_BASED_UNCOND_IO_EXITING)) + return 1; + + if (!nested_cpu_has(vmcs12, CPU_BASED_USE_IO_BITMAPS)) + return 0; + + exit_qualification = vmcs_readl(EXIT_QUALIFICATION); + + port = exit_qualification >> 16; + size = (exit_qualification & 7) + 1; + + last_bitmap = (gpa_t)-1; + b = -1; + + while (size > 0) { + if (port < 0x8000) + bitmap = vmcs12->io_bitmap_a; + else if (port < 0x10000) + bitmap = vmcs12->io_bitmap_b; + else + return 1; + bitmap += (port & 0x7fff) / 8; + + if (last_bitmap != bitmap) + if (kvm_read_guest(vcpu->kvm, bitmap, &b, 1)) + return 1; + if (b & (1 << (port & 7))) + return 1; + + port++; + size--; + last_bitmap = bitmap; + } + + return 0; +} + /* * Return 1 if we should exit from L2 to L1 to handle an MSR access access, * rather than handle it ourselves in L0. I.e., check whether L1 expressed @@ -6097,8 +6143,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu) case EXIT_REASON_DR_ACCESS: return nested_cpu_has(vmcs12, CPU_BASED_MOV_DR_EXITING); case EXIT_REASON_IO_INSTRUCTION: - /* TODO: support IO bitmaps */ - return 1; + return nested_vmx_exit_handled_io(vcpu, vmcs12); case EXIT_REASON_MSR_READ: case EXIT_REASON_MSR_WRITE: return nested_vmx_exit_handled_msr(vcpu, vmcs12, exit_reason); -- 2.39.5