Re: [PATCH v4 0/6] Nonatomic interrupt injection
On 09/17/2010 09:12 PM, Marcelo Tosatti wrote:
This is now merged, with the change pointed out by Marcelo. Windows
XP x64 fails installation without
(vmx.c handle_cr())
case 8: {
u8 cr8_prev = kvm_get_cr8(vcpu);
u8 cr8 = kvm_register_read(vcpu, reg);
kvm_set_cr8(vcpu, cr8);
skip_emulated_instruction(vcpu);
if (irqchip_in_kernel(vcpu-kvm))
return 1;
-if (cr8_prev= cr8)
-return 1;
vcpu-run-exit_reason = KVM_EXIT_SET_TPR;
return 0;
}
Which doesn't make any sense (anyone?). The failure is present even
without the patchset, and is fixed by the same hack, so a regression
was not introduced.
If userspace does not have an uptodate TPR value, it can signal an
interrupt that is now blocked? Say:
- cr8 write 0
- cr8 write 5
- no exit to userspace
- userspace signals interrupt with priority
4 because it knows about tpr == 0.
To signal an interrupt, userspace needs to force an exit. The exit will
sync cr8.
However, it may be that the decision to inject the interrupt is taken
before the exit, so the interrupt is injected even though it shouldn't be.
Let's assume that this is so (I'll check). Is this a bug in the kernel
or userspace?
My feeling is that this is a kernel bug, and the optimization should be
removed.
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Re: [PATCH v4 0/6] Nonatomic interrupt injection
On 09/19/2010 11:25 AM, Avi Kivity wrote: Let's assume that this is so (I'll check). It's trivially so. If a completion causes an interrupt to be raised, the vcpu's apic code is executed in the iothread context. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4 0/6] Nonatomic interrupt injection
On 09/19/2010 11:28 AM, Avi Kivity wrote: On 09/19/2010 11:25 AM, Avi Kivity wrote: Let's assume that this is so (I'll check). It's trivially so. If a completion causes an interrupt to be raised, the vcpu's apic code is executed in the iothread context. However, that's a bug even with the optimization removed: iothreadvcpu ioapic interrrupt apic: set isr mov $large_value, cr8 on_vcpu(inject) inject interrupt even though cr8 inhibits it Setting the isr and injecting the interrupt should be an atomic operation (easily done be running the apic code on the vcpu thread). -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4 0/6] Nonatomic interrupt injection
On Thu, Sep 16, 2010 at 03:35:19PM +0200, Avi Kivity wrote:
On 08/30/2010 02:36 PM, Avi Kivity wrote:
This patchset changes interrupt injection to be done from normal process
context instead of interrupts disabled context. This is useful for real
mode interrupt injection on Intel without the current hacks (injecting as
a software interrupt of a vm86 task), reducing latencies, and later, for
allowing nested virtualization code to use kvm_read_guest()/kvm_write_guest()
instead of kmap() to access the guest vmcb/vmcs.
Seems to survive a hack that cancels every 16th entry, after injection has
already taken place.
With the PIC reset fix posted earlier, this passes autotest on both AMD and
Intel, with in-kernel irqchip. I'll run -no-kvm-irqchip tests shortly.
Please review carefully, esp. the first patch. Any missing
kvm_make_request()
there may result in a hung guest.
This is now merged, with the change pointed out by Marcelo. Windows
XP x64 fails installation without
(vmx.c handle_cr())
case 8: {
u8 cr8_prev = kvm_get_cr8(vcpu);
u8 cr8 = kvm_register_read(vcpu, reg);
kvm_set_cr8(vcpu, cr8);
skip_emulated_instruction(vcpu);
if (irqchip_in_kernel(vcpu-kvm))
return 1;
-if (cr8_prev = cr8)
-return 1;
vcpu-run-exit_reason = KVM_EXIT_SET_TPR;
return 0;
}
Which doesn't make any sense (anyone?). The failure is present even
without the patchset, and is fixed by the same hack, so a regression
was not introduced.
If userspace does not have an uptodate TPR value, it can signal an
interrupt that is now blocked? Say:
- cr8 write 0
- cr8 write 5
- no exit to userspace
- userspace signals interrupt with priority
4 because it knows about tpr == 0.
--
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the body of a message to majord...@vger.kernel.org
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Re: [PATCH v4 0/6] Nonatomic interrupt injection
On 08/30/2010 02:36 PM, Avi Kivity wrote:
This patchset changes interrupt injection to be done from normal process
context instead of interrupts disabled context. This is useful for real
mode interrupt injection on Intel without the current hacks (injecting as
a software interrupt of a vm86 task), reducing latencies, and later, for
allowing nested virtualization code to use kvm_read_guest()/kvm_write_guest()
instead of kmap() to access the guest vmcb/vmcs.
Seems to survive a hack that cancels every 16th entry, after injection has
already taken place.
With the PIC reset fix posted earlier, this passes autotest on both AMD and
Intel, with in-kernel irqchip. I'll run -no-kvm-irqchip tests shortly.
Please review carefully, esp. the first patch. Any missing kvm_make_request()
there may result in a hung guest.
This is now merged, with the change pointed out by Marcelo. Windows XP
x64 fails installation without
(vmx.c handle_cr())
case 8: {
u8 cr8_prev = kvm_get_cr8(vcpu);
u8 cr8 = kvm_register_read(vcpu, reg);
kvm_set_cr8(vcpu, cr8);
skip_emulated_instruction(vcpu);
if (irqchip_in_kernel(vcpu-kvm))
return 1;
-if (cr8_prev = cr8)
-return 1;
vcpu-run-exit_reason = KVM_EXIT_SET_TPR;
return 0;
}
Which doesn't make any sense (anyone?). The failure is present even
without the patchset, and is fixed by the same hack, so a regression was
not introduced.
--
error compiling committee.c: too many arguments to function
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[PATCH v4 0/6] Nonatomic interrupt injection
This patchset changes interrupt injection to be done from normal process context instead of interrupts disabled context. This is useful for real mode interrupt injection on Intel without the current hacks (injecting as a software interrupt of a vm86 task), reducing latencies, and later, for allowing nested virtualization code to use kvm_read_guest()/kvm_write_guest() instead of kmap() to access the guest vmcb/vmcs. Seems to survive a hack that cancels every 16th entry, after injection has already taken place. With the PIC reset fix posted earlier, this passes autotest on both AMD and Intel, with in-kernel irqchip. I'll run -no-kvm-irqchip tests shortly. Please review carefully, esp. the first patch. Any missing kvm_make_request() there may result in a hung guest. v4: add KVM_REQ_EVENT after lapic restore v3: close new race between injection and entry fix Intel real-mode injection cancellation v2: svm support (easier than expected) fix silly vmx warning Avi Kivity (6): KVM: Check for pending events before attempting injection KVM: VMX: Split up vmx_complete_interrupts() KVM: VMX: Move real-mode interrupt injection fixup to vmx_complete_interrupts() KVM: VMX: Parameterize vmx_complete_interrupts() for both exit and entry KVM: Non-atomic interrupt injection KVM: VMX: Move fixup_rmode_irq() to avoid forward declaration arch/x86/include/asm/kvm_host.h |1 + arch/x86/kvm/i8259.c|1 + arch/x86/kvm/lapic.c| 13 - arch/x86/kvm/svm.c | 20 ++- arch/x86/kvm/vmx.c | 116 ++ arch/x86/kvm/x86.c | 44 ++ include/linux/kvm_host.h|1 + 7 files changed, 143 insertions(+), 53 deletions(-) -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4 0/6] Nonatomic interrupt injection
On 08/30/2010 02:36 PM, Avi Kivity wrote: I'll run -no-kvm-irqchip tests shortly. That needed a KVM_REQ_EVENT in the KVM_INTERRUPT path, but otherwise it's running smoothly. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
