- 10 Sep, 2009 40 commits
-
-
Gleb Natapov authored
Signed-off-by:
Gleb Natapov <gleb@redhat.com> Signed-off-by:
Avi Kivity <avi@redhat.com>
-
Joerg Roedel authored
Signed-off-by:
Joerg Roedel <joerg.roedel@amd.com> Signed-off-by:
-
Gregory Haskins authored
ioeventfd is a mechanism to register PIO/MMIO regions to trigger an eventfd signal when written to by a guest. Host userspace can register any arbitrary IO address with a corresponding eventfd and then pass the eventfd to a specific end-point of interest for handling. Normal IO requires a blocking round-trip since the operation may cause side-effects in the emulated model or may return data to the caller. Therefore, an IO in KVM traps from the guest to the host, causes a VMX/SVM "heavy-weight" exit back to userspace, and is ultimately serviced by qemu's device model synchronously before returning control back to the vcpu. However, there is a subclass of IO which acts purely as a trigger for other IO (such as to kick off an out-of-band DMA request, etc). For these patterns, the synchronous call is particularly expensive since we really only want to simply get our notification transmitted asychronously and return as quickly as possible. All the sychronous infrastructure to ensure proper data-dependencies are met in the normal IO case are just unecessary overhead for signalling. This adds additional computational load on the system, as well as latency to the signalling path. Therefore, we provide a mechanism for registration of an in-kernel trigger point that allows the VCPU to only require a very brief, lightweight exit just long enough to signal an eventfd. This also means that any clients compatible with the eventfd interface (which includes userspace and kernelspace equally well) can now register to be notified. The end result should be a more flexible and higher performance notification API for the backend KVM hypervisor and perhipheral components. To test this theory, we built a test-harness called "doorbell". This module has a function called "doorbell_ring()" which simply increments a counter for each time the doorbell is signaled. It supports signalling from either an eventfd, or an ioctl(). We then wired up two paths to the doorbell: One via QEMU via a registered io region and through the doorbell ioctl(). The other is direct via ioeventfd. You can download this test harness here: ftp://ftp.novell.com/dev/ghaskins/doorbell.tar.bz2 The measured results are as follows: qemu-mmio: 110000 iops, 9.09us rtt ioeventfd-mmio: 200100 iops, 5.00us rtt ioeventfd-pio: 367300 iops, 2.72us rtt I didn't measure qemu-pio, because I have to figure out how to register a PIO region with qemu's device model, and I got lazy. However, for now we can extrapolate based on the data from the NULLIO runs of +2.56us for MMIO, and -350ns for HC, we get: qemu-pio: 153139 iops, 6.53us rtt ioeventfd-hc: 412585 iops, 2.37us rtt these are just for fun, for now, until I can gather more data. Here is a graph for your convenience: http://developer.novell.com/wiki/images/7/76/Iofd-chart.png The conclusion to draw is that we save about 4us by skipping the userspace hop. -------------------- Signed-off-by:
Gregory Haskins <ghaskins@novell.com> Acked-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
-
Gregory Haskins authored
Today kvm_io_bus_regsiter_dev() returns void and will internally BUG_ON if it fails. We want to create dynamic MMIO/PIO entries driven from userspace later in the series, so we need to enhance the code to be more robust with the following changes: 1) Add a return value to the registration function 2) Fix up all the callsites to check the return code, handle any failures, and percolate the error up to the caller. 3) Add an unregister function that collapses holes in the array Signed-off-by: -
Andre Przywara authored
Signed-off-by:
Andre Przywara <andre.przywara@amd.com> Signed-off-by:
-
Beth Kon authored
When kvm is in hpet_legacy_mode, the hpet is providing the timer interrupt and the pit should not be. So in legacy mode, the pit timer is destroyed, but the *state* of the pit is maintained. So if kvm or the guest tries to modify the state of the pit, this modification is accepted, *except* that the timer isn't actually started. When we exit hpet_legacy_mode, the current state of the pit (which is up to date since we've been accepting modifications) is used to restart the pit timer. The saved_mode code in kvm_pit_load_count temporarily changes mode to 0xff in order to destroy the timer, but then restores the actual value, again maintaining "current" state of the pit for possible later reenablement. [avi: add some reserved storage in the ioctl; make SET_PIT2 IOW] [marcelo: fix memory corruption due to reserved storage] Signed-off-by:
Beth Kon <eak@us.ibm.com> Signed-off-by:
Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:
-
Gleb Natapov authored
We emulate x2apic in software, so host support is not required. Signed-off-by:
-
Gleb Natapov authored
This will save a couple of IPIs. Signed-off-by:
-
Gleb Natapov authored
Add tracepoint in msi/ioapic/pic set_irq() functions, in IPI sending and in the point where IRQ is placed into apic's IRR. Signed-off-by:
-
Michael S. Tsirkin authored
Irqfd sets level for interrupt to 1 and then to 0. For MSI, check level so that a single message is sent. Signed-off-by:
-
Andre Przywara authored
Some Windows versions check whether the BIOS has setup MMI/O for config space accesses on AMD Fam10h CPUs, we say "no" by returning 0 on reads and only allow disabling of MMI/O CfgSpace setup by igoring "0" writes. Signed-off-by:
-
Avi Kivity authored
Create, sync, unsync, zap. Signed-off-by: -
Avi Kivity authored
Document the basic API corresponding to the 2.6.22 release. Signed-off-by: -
Avi Kivity authored
Signed-off-by: -
Jan Kiszka authored
This reverts commit 6c20e1442bb1c62914bb85b7f4a38973d2a423ba. To my understanding, it became obsolete with the advent of the more robust check in mmu_alloc_roots (89da4ff17f). Moreover, it prevents the conceptually safe pattern 1. set sregs 2. register mem-slots 3. run vcpu by setting a sticky triple fault during step 1. Signed-off-by:
Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by:
-
Andre Przywara authored
Windows 7 tries to update the CPU's microcode on some processors, so we ignore the MSR write here. The patchlevel register is already handled (returning 0), because the MSR number is the same as Intel's. Signed-off-by:
-
Sheng Yang authored
Some in-famous OS do unaligned writing for APIC MMIO, and the return value has been missed in recent change, then the OS hangs. Signed-off-by:
Sheng Yang <sheng@linux.intel.com> Signed-off-by:
-
Gleb Natapov authored
Cosmetic only. No logic is changed by this patch. Signed-off-by:
-
Gleb Natapov authored
This patch implements MSR interface to local apic as defines by x2apic Intel specification. Signed-off-by:
-
Gleb Natapov authored
Directed EOI is specified by x2APIC, but is available even when lapic is in xAPIC mode. Signed-off-by:
-
Avi Kivity authored
Signed-off-by: -
Avi Kivity authored
Signed-off-by: -
Andre Przywara authored
Linux guests will try to enable access to the extended PCI config space via the I/O ports 0xCF8/0xCFC on AMD Fam10h CPU. Since we (currently?) don't use ECS, simply ignore write and read attempts. Signed-off-by:
-
Avi Kivity authored
Signed-off-by: -
Jiri Slaby authored
There is a missing unlock on one fail path in ioapic_mmio_write, fix that. Signed-off-by:
Jiri Slaby <jirislaby@gmail.com> Signed-off-by:
-
Michael S. Tsirkin authored
Document kvm->lock nesting within kvm->slots_lock Signed-off-by:
-
Michael S. Tsirkin authored
This changes bus accesses to use high-level kvm_io_bus_read/kvm_io_bus_write functions. in_range now becomes unused so it is removed from device ops in favor of read/write callbacks performing range checks internally. This allows aliasing (mostly for in-kernel virtio), as well as better error handling by making it possible to pass errors up to userspace. Signed-off-by:
-
Michael S. Tsirkin authored
Use slots_lock to protect device list on the bus. slots_lock is already taken for read everywhere, so we only need to take it for write when registering devices. This is in preparation to removing in_range and kvm->lock around it. Signed-off-by:
-
Michael S. Tsirkin authored
switch pit creation to slots_lock. slots_lock is already taken for read everywhere, so we only need to take it for write when creating pit. This is in preparation to removing in_range and kvm->lock around it. Signed-off-by:
-
Michael S. Tsirkin authored
switch coalesced mmio slots_lock. slots_lock is already taken for read everywhere, so we only need to take it for write when changing zones. This is in preparation to removing in_range and kvm->lock around it. [avi: fix build] Signed-off-by:
-
Michael S. Tsirkin authored
slots_lock is taken everywhere when device ops are called. Document this as we will use this to rework locking for io. Signed-off-by:
-
Marcelo Tosatti authored
Change kvm_vcpu_is_bsp to use vcpu_id instead of bsp_vcpu pointer, which is only initialized at the end of kvm_vm_ioctl_create_vcpu. Signed-off-by:
-
Marcelo Tosatti authored
Return EOPNOTSUPP for KVM_TRACE_ENABLE/PAUSE/DISABLE ioctls. Signed-off-by:
-
Marcelo Tosatti authored
[avi: make it build] [avi: fold trace-arch.h into trace.h] CC: Hollis Blanchard <hollisb@us.ibm.com> Signed-off-by:
-
Andre Przywara authored
KVM will inject a #GP into the guest if that tries to access unhandled MSRs. This will crash many guests. Although it would be the correct way to actually handle these MSRs, we introduce a runtime switchable module param called "ignore_msrs" (defaults to 0). If this is Y, unknown MSR reads will return 0, while MSR writes are simply dropped. In both cases we print a message to dmesg to inform the user about that. You can change the behaviour at any time by saying: # echo 1 > /sys/modules/kvm/parameters/ignore_msrs Signed-off-by:
-
Andre Przywara authored
If the Linux kernel detects an C1E capable AMD processor (K8 RevF and higher), it will access a certain MSR on every attempt to go to halt. Explicitly handle this read and return 0 to let KVM run a Linux guest with the native AMD host CPU propagated to the guest. Signed-off-by:
-
Andre Przywara authored
Linux tries to disable the flush filter on all AMD K8 CPUs. Since KVM does not handle the needed MSR, the injected #GP will panic the Linux kernel. Ignore setting of the HWCR.FFDIS bit in this MSR to let Linux boot with an AMD K8 family guest CPU. Signed-off-by:
-
Marcelo Tosatti authored
Correct missing locking in a few places in x86's vm_ioctl handling path. Signed-off-by:
-
Joerg Roedel authored
[avi: fix build on non-x86] Signed-off-by:
-
Joerg Roedel authored
This function is required by KVM. Signed-off-by:
-
