- 06 Dec, 2012 9 commits
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Paul Mackerras authored
This fixes a bug in the code which allows userspace to read out the contents of the guest's hashed page table (HPT). On the second and subsequent passes through the HPT, when we are reporting only those entries that have changed, we were incorrectly initializing the index field of the header with the index of the first entry we skipped rather than the first changed entry. This fixes it. Signed-off-by:
Paul Mackerras <paulus@samba.org> Signed-off-by:
Alexander Graf <agraf@suse.de>
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Paul Mackerras authored
With HV-style KVM, we maintain reverse-mapping lists that enable us to find all the HPT (hashed page table) entries that reference each guest physical page, with the heads of the lists in the memslot->arch.rmap arrays. When we reset the HPT (i.e. when we reboot the VM), we clear out all the HPT entries but we were not clearing out the reverse mapping lists. The result is that as we create new HPT entries, the lists get corrupted, which can easily lead to loops, resulting in the host kernel hanging when it tries to traverse those lists. This fixes the problem by zeroing out all the reverse mapping lists when we zero out the HPT. This incidentally means that we are also zeroing our record of the referenced and changed bits (not the bits in the Linux PTEs, used by the Linux MM subsystem, but the bits used by the KVM_GET_DIRTY_LOG ioctl, and those used by kvm_age_hva() and kvm_test_age_hva()). Signed-off-by:
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Paul Mackerras authored
A new ioctl, KVM_PPC_GET_HTAB_FD, returns a file descriptor. Reads on this fd return the contents of the HPT (hashed page table), writes create and/or remove entries in the HPT. There is a new capability, KVM_CAP_PPC_HTAB_FD, to indicate the presence of the ioctl. The ioctl takes an argument structure with the index of the first HPT entry to read out and a set of flags. The flags indicate whether the user is intending to read or write the HPT, and whether to return all entries or only the "bolted" entries (those with the bolted bit, 0x10, set in the first doubleword). This is intended for use in implementing qemu's savevm/loadvm and for live migration. Therefore, on reads, the first pass returns information about all HPTEs (or all bolted HPTEs). When the first pass reaches the end of the HPT, it returns from the read. Subsequent reads only return information about HPTEs that have changed since they were last read. A read that finds no changed HPTEs in the HPT following where the last read finished will return 0 bytes. The format of the data provides a simple run-length compression of the invalid entries. Each block of data starts with a header that indicates the index (position in the HPT, which is just an array), the number of valid entries starting at that index (may be zero), and the number of invalid entries following those valid entries. The valid entries, 16 bytes each, follow the header. The invalid entries are not explicitly represented. Signed-off-by:
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Paul Mackerras authored
This makes a HPTE removal function, kvmppc_do_h_remove(), available outside book3s_hv_rm_mmu.c. This will be used by the HPT writing code. Signed-off-by:
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Paul Mackerras authored
This uses a bit in our record of the guest view of the HPTE to record when the HPTE gets modified. We use a reserved bit for this, and ensure that this bit is always cleared in HPTE values returned to the guest. The recording of modified HPTEs is only done if other code indicates its interest by setting kvm->arch.hpte_mod_interest to a non-zero value. The reason for this is that when later commits add facilities for userspace to read the HPT, the first pass of reading the HPT will be quicker if there are no (or very few) HPTEs marked as modified, rather than having most HPTEs marked as modified. Signed-off-by:
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Paul Mackerras authored
This fixes a bug where adding a new guest HPT entry via the H_ENTER hcall would lose the "changed" bit in the reverse map information for the guest physical page being mapped. The result was that the KVM_GET_DIRTY_LOG could return a zero bit for the page even though the page had been modified by the guest. This fixes it by only modifying the index and present bits in the reverse map entry, thus preserving the reference and change bits. We were also unnecessarily setting the reference bit, and this fixes that too. Signed-off-by:
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Paul Mackerras authored
This restructures the code that creates HPT (hashed page table) entries so that it can be called in situations where we don't have a struct vcpu pointer, only a struct kvm pointer. It also fixes a bug where kvmppc_map_vrma() would corrupt the guest R4 value. Most of the work of kvmppc_virtmode_h_enter is now done by a new function, kvmppc_virtmode_do_h_enter, which itself calls another new function, kvmppc_do_h_enter, which contains most of the old kvmppc_h_enter. The new kvmppc_do_h_enter takes explicit arguments for the place to return the HPTE index, the Linux page tables to use, and whether it is being called in real mode, thus removing the need for it to have the vcpu as an argument. Currently kvmppc_map_vrma creates the VRMA (virtual real mode area) HPTEs by calling kvmppc_virtmode_h_enter, which is designed primarily to handle H_ENTER hcalls from the guest that need to pin a page of memory. Since H_ENTER returns the index of the created HPTE in R4, kvmppc_virtmode_h_enter updates the guest R4, corrupting the guest R4 in the case when it gets called from kvmppc_map_vrma on the first VCPU_RUN ioctl. With this, kvmppc_map_vrma instead calls kvmppc_virtmode_do_h_enter with the address of a dummy word as the place to store the HPTE index, thus avoiding corrupting the guest R4. Signed-off-by:
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Alexander Graf authored
In order to support the generic eventfd infrastructure on PPC, we need to call into the generic KVM in-kernel device mmio code. Signed-off-by: -
Alexander Graf authored
The current eventfd code assumes that when we have eventfd, we also have irqfd for in-kernel interrupt delivery. This is not necessarily true. On PPC we don't have an in-kernel irqchip yet, but we can still support easily support eventfd. Signed-off-by:
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- 02 Dec, 2012 1 commit
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Jan Kiszka authored
This is a regression caused by 18595411. Signed-off-by:
Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by:
Gleb Natapov <gleb@redhat.com>
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- 30 Nov, 2012 3 commits
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Will Auld authored
CPUID.7.0.EBX[1]=1 indicates IA32_TSC_ADJUST MSR 0x3b is supported Basic design is to emulate the MSR by allowing reads and writes to a guest vcpu specific location to store the value of the emulated MSR while adding the value to the vmcs tsc_offset. In this way the IA32_TSC_ADJUST value will be included in all reads to the TSC MSR whether through rdmsr or rdtsc. This is of course as long as the "use TSC counter offsetting" VM-execution control is enabled as well as the IA32_TSC_ADJUST control. However, because hardware will only return the TSC + IA32_TSC_ADJUST + vmsc tsc_offset for a guest process when it does and rdtsc (with the correct settings) the value of our virtualized IA32_TSC_ADJUST must be stored in one of these three locations. The argument against storing it in the actual MSR is performance. This is likely to be seldom used while the save/restore is required on every transition. IA32_TSC_ADJUST was created as a way to solve some issues with writing TSC itself so that is not an option either. The remaining option, defined above as our solution has the problem of returning incorrect vmcs tsc_offset values (unless we intercept and fix, not done here) as mentioned above. However, more problematic is that storing the data in vmcs tsc_offset will have a different semantic effect on the system than does using the actual MSR. This is illustrated in the following example: The hypervisor set the IA32_TSC_ADJUST, then the guest sets it and a guest process performs a rdtsc. In this case the guest process will get TSC + IA32_TSC_ADJUST_hyperviser + vmsc tsc_offset including IA32_TSC_ADJUST_guest. While the total system semantics changed the semantics as seen by the guest do not and hence this will not cause a problem. Signed-off-by:
Will Auld <will.auld@intel.com> Signed-off-by:
Marcelo Tosatti <mtosatti@redhat.com>
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Will Auld authored
In order to track who initiated the call (host or guest) to modify an msr value I have changed function call parameters along the call path. The specific change is to add a struct pointer parameter that points to (index, data, caller) information rather than having this information passed as individual parameters. The initial use for this capability is for updating the IA32_TSC_ADJUST msr while setting the tsc value. It is anticipated that this capability is useful for other tasks. Signed-off-by:
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Alex Williamson authored
Prior to memory slot sorting this loop compared all of the user memory slots for overlap with new entries. With memory slot sorting, we're just checking some number of entries in the array that may or may not be user slots. Instead, walk all the slots with kvm_for_each_memslot, which has the added benefit of terminating early when we hit the first empty slot, and skip comparison to private slots. Cc: stable@vger.kernel.org Signed-off-by:
Alex Williamson <alex.williamson@redhat.com> Signed-off-by:
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- 29 Nov, 2012 2 commits
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Xiao Guangrong authored
vmcs->cpu indicates whether it exists on the target cpu, -1 means the vmcs does not exist on any vcpu If vcpu load vmcs with vmcs.cpu = -1, it can be directly added to cpu's percpu list. The list can be corrupted if the cpu prefetch the vmcs's list before reading vmcs->cpu. Meanwhile, we should remove vmcs from the list before making vmcs->vcpu == -1 be visible Signed-off-by:
Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by:
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Xiao Guangrong authored
In loaded_vmcs_clear, loaded_vmcs->cpu is the fist parameter passed to smp_call_function_single, if the target cpu is downing (doing cpu hot remove), loaded_vmcs->cpu can become -1 then -1 is passed to smp_call_function_single It can be triggered when vcpu is being destroyed, loaded_vmcs_clear is called in the preemptionable context Signed-off-by:
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- 28 Nov, 2012 19 commits
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Gleb Natapov authored
As Frederic pointed idle_cpu() may return false even if async fault happened in the idle task if wake up is pending. In this case the code will try to put idle task to sleep. Fix this by using is_idle_task() to check for idle task. Reported-by:
Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by:
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Marcelo Tosatti authored
As requested by Glauber, do not update kvmclock area on vcpu->pcpu migration, in case the host has stable TSC. This is to reduce cacheline bouncing. Acked-by:
Glauber Costa <glommer@parallels.com> Signed-off-by:
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Marcelo Tosatti authored
With master clock, a pvclock clock read calculates: ret = system_timestamp + [ (rdtsc + tsc_offset) - tsc_timestamp ] Where 'rdtsc' is the host TSC. system_timestamp and tsc_timestamp are unique, one tuple per VM: the "master clock". Given a host with synchronized TSCs, its obvious that guest TSC must be matched for the above to guarantee monotonicity. Allow master clock usage only if guest TSCs are synchronized. Signed-off-by: -
Marcelo Tosatti authored
TSC initialization will soon make use of online_vcpus. Signed-off-by: -
Marcelo Tosatti authored
KVM added a global variable to guarantee monotonicity in the guest. One of the reasons for that is that the time between 1. ktime_get_ts(×pec); 2. rdtscll(tsc); Is variable. That is, given a host with stable TSC, suppose that two VCPUs read the same time via ktime_get_ts() above. The time required to execute 2. is not the same on those two instances executing in different VCPUS (cache misses, interrupts...). If the TSC value that is used by the host to interpolate when calculating the monotonic time is the same value used to calculate the tsc_timestamp value stored in the pvclock data structure, and a single <system_timestamp, tsc_timestamp> tuple is visible to all vcpus simultaneously, this problem disappears. See comment on top of pvclock_update_vm_gtod_copy for details. Monotonicity is then guaranteed by synchronicity of the host TSCs and guest TSCs. Set TSC stable pvclock flag in that case, allowing the guest to read clock from userspace. Signed-off-by: -
Marcelo Tosatti authored
Register a notifier for clocksource change event. In case the host switches to clock other than TSC, disable master clock usage. Signed-off-by: -
Marcelo Tosatti authored
As suggested by John, export time data similarly to how its done by vsyscall support. This allows KVM to retrieve necessary information to implement vsyscall support in KVM guests. Acked-by:
John Stultz <johnstul@us.ibm.com> Signed-off-by:
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Marcelo Tosatti authored
Allow the caller to pass host tsc value to kvm_x86_ops->read_l1_tsc(). Signed-off-by: -
Marcelo Tosatti authored
Improve performance of time system calls when using Linux pvclock, by reading time info from fixmap visible copy of pvclock data. Originally from Jeremy Fitzhardinge. Signed-off-by: -
Marcelo Tosatti authored
Hook into generic pvclock vsyscall code, with the aim to allow userspace to have visibility into pvclock data. Signed-off-by: -
Marcelo Tosatti authored
Originally from Jeremy Fitzhardinge. Introduce generic, non hypervisor specific, pvclock initialization routines. Signed-off-by: -
Marcelo Tosatti authored
Originally from Jeremy Fitzhardinge. Acked-by:
Ingo Molnar <mingo@redhat.com> Signed-off-by:
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Marcelo Tosatti authored
As noted by Gleb, not advertising SSE2 support implies no RDTSC barriers. Signed-off-by: -
Marcelo Tosatti authored
Acked-by:
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Marcelo Tosatti authored
Originally from Jeremy Fitzhardinge. So code can be reused. Acked-by:
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Marcelo Tosatti authored
Originally from Jeremy Fitzhardinge. We can copy the information directly from "struct pvclock_vcpu_time_info", remove pvclock_shadow_time. Reviewed-by:
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Marcelo Tosatti authored
Originally from Jeremy Fitzhardinge. pvclock_get_time_values, which contains the memory barriers will be removed by next patch. Signed-off-by: -
Marcelo Tosatti authored
We want to expose the pvclock shared memory areas, which the hypervisor periodically updates, to userspace. For a linear mapping from userspace, it is necessary that entire page sized regions are used for array of pvclock structures. There is no such guarantee with per cpu areas, therefore move to memblock_alloc based allocation. Acked-by:
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Marcelo Tosatti authored
Otherwise its possible for an unrelated KVM_REQ_UPDATE_CLOCK (such as due to CPU migration) to clear the bit. Noticed by Paolo Bonzini. Reviewed-by:
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- 14 Nov, 2012 3 commits
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Guo Chao authored
No need to check return value before breaking switch. Signed-off-by:
Guo Chao <yan@linux.vnet.ibm.com> Signed-off-by:
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Guo Chao authored
Return value of this function will be that of ioctl(). #include <stdio.h> #include <linux/kvm.h> int main () { int fd; fd = open ("/dev/kvm", 0); fd = ioctl (fd, KVM_CREATE_VM, 0); ioctl (fd, KVM_SET_TSS_ADDR, 0xfffff000); perror (""); return 0; } Output is "Operation not permitted". That's not what we want. Return -EINVAL in this case. Signed-off-by: -
Guo Chao authored
We should avoid kfree()ing error pointer in kvm_vcpu_ioctl() and kvm_arch_vcpu_ioctl(). Signed-off-by:
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- 01 Nov, 2012 2 commits
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https://github.com/agraf/linux-2.6Marcelo Tosatti authored
* 'for-queue' of https://github.com/agraf/linux-2.6: PPC: ePAPR: Convert hcall header to uapi (round 2) KVM: PPC: Book3S HV: Fix thinko in try_lock_hpte() KVM: PPC: Book3S HV: Allow DTL to be set to address 0, length 0 KVM: PPC: Book3S HV: Fix accounting of stolen time KVM: PPC: Book3S HV: Run virtual core whenever any vcpus in it can run KVM: PPC: Book3S HV: Fixes for late-joining threads KVM: PPC: Book3s HV: Don't access runnable threads list without vcore lock KVM: PPC: Book3S HV: Fix some races in starting secondary threads KVM: PPC: Book3S HV: Allow KVM guests to stop secondary threads coming online PPC: ePAPR: Convert header to uapi KVM: PPC: Move mtspr/mfspr emulation into own functions KVM: Documentation: Fix reentry-to-be-consistent paragraph KVM: PPC: 44x: fix DCR read/write
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Joerg Roedel authored
I have no access to my AMD email address anymore. Update entry in MAINTAINERS to the new address. Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:
Joerg Roedel <joro@8bytes.org> Signed-off-by:
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- 31 Oct, 2012 1 commit
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Alexander Graf authored
The new uapi framework splits kernel internal and user space exported bits of header files more cleanly. Adjust the ePAPR header accordingly. Signed-off-by:
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