- 25 Sep, 2011 40 commits
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Paul Mackerras authored
With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by:
Paul Mackerras <paulus@samba.org> Signed-off-by:
Alexander Graf <agraf@suse.de>
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Paul Mackerras authored
This simplifies the way that the book3s_pr makes the transition to real mode when entering the guest. We now call kvmppc_entry_trampoline (renamed from kvmppc_rmcall) in the base kernel using a normal function call instead of doing an indirect call through a pointer in the vcpu. If kvm is a module, the module loader takes care of generating a trampoline as it does for other calls to functions outside the module. kvmppc_entry_trampoline then disables interrupts and jumps to kvmppc_handler_trampoline_enter in real mode using an rfi[d]. That then uses the link register as the address to return to (potentially in module space) when the guest exits. This also simplifies the way that we call the Linux interrupt handler when we exit the guest due to an external, decrementer or performance monitor interrupt. Instead of turning on the MMU, then deciding that we need to call the Linux handler and turning the MMU back off again, we now go straight to the handler at the point where we would turn the MMU on. The handler will then return to the virtual-mode code (potentially in the module). Along the way, this moves the setting and clearing of the HID5 DCBZ32 bit into real-mode interrupts-off code, and also makes sure that we clear the MSR[RI] bit before loading values into SRR0/1. The net result is that we no longer need any code addresses to be stored in vcpu->arch. Signed-off-by:
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Paul Mackerras authored
This makes arch/powerpc/kvm/book3s_rmhandlers.S and arch/powerpc/kvm/book3s_hv_rmhandlers.S be assembled as separate compilation units rather than having them #included in arch/powerpc/kernel/exceptions-64s.S. We no longer have any conditional branches between the exception prologs in exceptions-64s.S and the KVM handlers, so there is no need to keep their contents close together in the vmlinux image. In their current location, they are using up part of the limited space between the first-level interrupt handlers and the firmware NMI data area at offset 0x7000, and with some kernel configurations this area will overflow (e.g. allyesconfig), leading to an "attempt to .org backwards" error when compiling exceptions-64s.S. Moving them out requires that we add some #includes that the book3s_{,hv_}rmhandlers.S code was previously getting implicitly via exceptions-64s.S. Signed-off-by: -
Alexander Graf authored
There are multiple features in PowerPC KVM that can now be enabled depending on the user's wishes. Some of the combinations don't make sense or don't work though. So this patch adds a way to check if the executing environment would actually be able to run the guest properly. It also adds sanity checks if PVR is set (should always be true given the current code flow), if PAPR is only used with book3s_64 where it works and that HV KVM is only used in PAPR mode. Signed-off-by: -
Alexander Graf authored
Now that Book3S PV mode can also run PAPR guests, we can add a PAPR cap and enable it for all Book3S targets. Enabling that CAP switches KVM into PAPR mode. Signed-off-by: -
Alexander Graf authored
PAPR defines hypercalls as SC1 instructions. Using these, the guest modifies page tables and does other privileged operations that it wouldn't be allowed to do in supervisor mode. This patch adds support for PR KVM to trap these instructions and route them through the same PAPR hypercall interface that we already use for HV style KVM. Signed-off-by: -
Alexander Graf authored
Recent Linux versions use the CFAR and PURR SPRs, but don't really care about their contents (yet). So for now, we can simply return 0 when the guest wants to read them. Signed-off-by: -
Alexander Graf authored
When running a PAPR guest, we need to handle a few hypercalls in kernel space, most prominently the page table invalidation (to sync the shadows). So this patch adds handling for a few PAPR hypercalls to PR mode KVM. I tried to share the code with HV mode, but it ended up being a lot easier this way around, as the two differ too much in those details. Signed-off-by: -
Alexander Graf authored
Until now, we always set HIOR based on the PVR, but this is just wrong. Instead, we should be setting HIOR explicitly, so user space can decide what the initial HIOR value is - just like on real hardware. We keep the old PVR based way around for backwards compatibility, but once user space uses the SREGS based method, we drop the PVR logic. Signed-off-by: -
Alexander Graf authored
We have a few traps where we cache the instruction that cause the trap for analysis later on. Since we now need to be able to distinguish between SC 0 and SC 1 system calls and the only way to find out which is which is by looking at the instruction, we also read out the instruction causing the system call. Signed-off-by: -
Alexander Graf authored
When running a PAPR guest, the guest is not allowed to set SDR1 - instead the HTAB information is held in internal hypervisor structures. But all of our current code relies on SDR1 and walking the HTAB like on real hardware. So in order to not be too intrusive, we simply set SDR1 to the HTAB we hold in host memory. That way we can keep the HTAB in user space, but use it from kernel space to map the guest. Signed-off-by: -
Alexander Graf authored
We have 3 privilege levels: problem state, supervisor state and hypervisor state. Each of them can access different SPRs, so we need to check on every SPR if it's accessible in the respective mode. Signed-off-by: -
Alexander Graf authored
When running a PAPR guest, some things change. The privilege level drops from hypervisor to supervisor, SDR1 gets treated differently and we interpret hypercalls. For bisectability sake, add the flag now, but only enable it when all the support code is there. Signed-off-by: -
Alexander Graf authored
We need the compute_tlbie_rb in _pr and _hv implementations for papr soon, so let's move it over to a common header file that both implementations can leverage. Signed-off-by: -
Avi Kivity authored
Commit 371fefd6 lost a doc hunk somehow, restore it. Signed-off-by:
Avi Kivity <avi@redhat.com>
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Kevin Tian authored
Instruction emulation for EOI writes can be skipped, since sane guest simply uses MOV instead of string operations. This is a nice improvement when guest doesn't support x2apic or hyper-V EOI support. a single VM bandwidth is observed with ~8% bandwidth improvement (7.4Gbps->8Gbps), by saving ~5% cycles from EOI emulation. Signed-off-by:
Kevin Tian <kevin.tian@intel.com> <Based on earlier work from>: Signed-off-by:
Eddie Dong <eddie.dong@intel.com> Signed-off-by:
Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:
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Nadav Har'El authored
When the TSC MSR is read by an L2 guest (when L1 allowed this MSR to be read without exit), we need to return L2's notion of the TSC, not L1's. The current code incorrectly returned L1 TSC, because svm_get_msr() was also used in x86.c where this was assumed, but now that these places call the new svm_read_l1_tsc(), the MSR read can be fixed. Signed-off-by:
Nadav Har'El <nyh@il.ibm.com> Tested-by:
Joerg Roedel <joerg.roedel@amd.com> Acked-by:
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Nadav Har'El authored
This patch fixes two corner cases in nested (L2) handling of TSC-related issues: 1. Somewhat suprisingly, according to the Intel spec, if L1 allows WRMSR to the TSC MSR without an exit, then this should set L1's TSC value itself - not offset by vmcs12.TSC_OFFSET (like was wrongly done in the previous code). 2. Allow L1 to disable the TSC_OFFSETING control, and then correctly ignore the vmcs12.TSC_OFFSET. Signed-off-by:
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Nadav Har'El authored
KVM assumed in several places that reading the TSC MSR returns the value for L1. This is incorrect, because when L2 is running, the correct TSC read exit emulation is to return L2's value. We therefore add a new x86_ops function, read_l1_tsc, to use in places that specifically need to read the L1 TSC, NOT the TSC of the current level of guest. Note that one change, of one line in kvm_arch_vcpu_load, is made redundant by a different patch sent by Zachary Amsden (and not yet applied): kvm_arch_vcpu_load() should not read the guest TSC, and if it didn't, of course we didn't have to change the call of kvm_get_msr() to read_l1_tsc(). [avi: moved callback to kvm_x86_ops tsc block] Signed-off-by:
Zachary Amsdem <zamsden@gmail.com> Signed-off-by:
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Sasha Levin authored
Add documentation of the new 'nested' parameter to 'Documentation/kernel-parameters.txt'. Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Nadav Har'El <nyh@il.ibm.com> Signed-off-by:
Sasha Levin <levinsasha928@gmail.com> Signed-off-by:
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Yang, Wei Y authored
This patch fix kvm-unit-tests hanging and incorrect PT_ACCESSED_MASK bit set in the case of SMEP fault. The code updated 'eperm' after the variable was checked. Signed-off-by:
Yang, Wei <wei.y.yang@intel.com> Signed-off-by:
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Avi Kivity authored
Architecturally, PDPTEs are cached in the PDPTRs when CR3 is reloaded. On SVM, it is not possible to implement this, but on VMX this is possible and was indeed implemented until nested SVM changed this to unconditionally read PDPTEs dynamically. This has noticable impact when running PAE guests. Fix by changing the MMU to read PDPTRs from the cache, falling back to reading from memory for the nested MMU. Signed-off-by:
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Julia Lawall authored
Use BUG_ON(x) rather than if(x) BUG(); The semantic patch that fixes this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ identifier x; @@ -if (x) BUG(); +BUG_ON(x); @@ identifier x; @@ -if (!x) BUG(); +BUG_ON(!x); // </smpl> Signed-off-by:
Julia Lawall <julia@diku.dk> Signed-off-by:
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Marcelo Tosatti authored
Windows Server 2008 SP2 checked build with smp > 1 BSOD's during boot due to lack of microcode update: *** Assertion failed: The system BIOS on this machine does not properly support the processor. The system BIOS did not load any microcode update. A BIOS containing the latest microcode update is needed for system reliability. (CurrentUpdateRevision != 0) *** Source File: d:\longhorn\base\hals\update\intelupd\update.c, line 440 Report a non-zero microcode update signature to make it happy. Signed-off-by:
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Takuya Yoshikawa authored
Return EMULATION_OK/FAILED consistently. Also treat instruction fetch errors, not restricted to X86EMUL_UNHANDLEABLE, as EMULATION_FAILED; although this cannot happen in practice, the current logic will continue the emulation even if the decoder fails to fetch the instruction. Signed-off-by:
Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by:
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Takuya Yoshikawa authored
Fetching the instruction which was to be executed by the guest cannot fail normally. So compiler should always predict that it will succeed. Signed-off-by:
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Takuya Yoshikawa authored
_type is enough to know the size. Signed-off-by:
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Takuya Yoshikawa authored
Instead of passing ctxt->_eip from insn_fetch() call sites, get it from ctxt in do_insn_fetch_byte(). This is done by replacing the argument _eip of insn_fetch() with _ctxt, which should be better than letting the macro use ctxt silently in its body. Though this changes the place where ctxt->_eip is incremented from insn_fetch() to do_insn_fetch_byte(), this does not have any real effect. Signed-off-by:
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Sasha Levin authored
Currently the method of dealing with an IO operation on a bus (PIO/MMIO) is to call the read or write callback for each device registered on the bus until we find a device which handles it. Since the number of devices on a bus can be significant due to ioeventfds and coalesced MMIO zones, this leads to a lot of overhead on each IO operation. Instead of registering devices, we now register ranges which points to a device. Lookup is done using an efficient bsearch instead of a linear search. Performance test was conducted by comparing exit count per second with 200 ioeventfds created on one byte and the guest is trying to access a different byte continuously (triggering usermode exits). Before the patch the guest has achieved 259k exits per second, after the patch the guest does 274k exits per second. Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:
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Stefan Hajnoczi authored
The vmexit tracepoints format the exit_reason to make it human-readable. Since the exit_reason depends on the instruction set (vmx or svm), formatting is handled with ftrace_print_symbols_seq() by referring to the appropriate exit reason table. However, the ftrace_print_symbols_seq() function is not meant to be used directly in tracepoints since it does not export the formatting table which userspace tools like trace-cmd and perf use to format traces. In practice perf dies when formatting vmexit-related events and trace-cmd falls back to printing the numeric value (with extra formatting code in the kvm plugin to paper over this limitation). Other userspace consumers of vmexit-related tracepoints would be in similar trouble. To avoid significant changes to the kvm_exit tracepoint, this patch moves the vmx and svm exit reason tables into arch/x86/kvm/trace.h and selects the right table with __print_symbolic() depending on the instruction set. Note that __print_symbolic() is designed for exporting the formatting table to userspace and allows trace-cmd and perf to work. Signed-off-by:
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by:
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Stefan Hajnoczi authored
The kvm_exit tracepoint recently added the isa argument to aid decoding exit_reason. The semantics of exit_reason depend on the instruction set (vmx or svm) and the isa argument allows traces to be analyzed on other machines. Add the isa argument to kvm_nested_vmexit and kvm_nested_vmexit_inject so these tracepoints can also be self-describing. Signed-off-by:
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Mike Waychison authored
Commit 0945d4b228 tried to fix the get_msr path for the HV_X64_MSR_APIC_ASSIST_PAGE msr, but was poorly tested. We should be returning 0 if the read succeeded, and passing the value back to the caller via the pdata out argument, not returning the value directly. Signed-off-by:
Mike Waychison <mikew@google.com> Signed-off-by:
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Mike Waychison authored
"get" support for the HV_X64_MSR_APIC_ASSIST_PAGE msr was missing, even though it is explicitly enumerated as something the vmm should save in msrs_to_save and reported to userland via the KVM_GET_MSR_INDEX_LIST ioctl. Add "get" support for HV_X64_MSR_APIC_ASSIST_PAGE. We simply return the guest visible value of this register, which seems to be correct as a set on the register is validated for us already. Signed-off-by:
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Sasha Levin authored
This patch changes coalesced mmio to create one mmio device per zone instead of handling all zones in one device. Doing so enables us to take advantage of existing locking and prevents a race condition between coalesced mmio registration/unregistration and lookups. Suggested-by:
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Sasha Levin authored
The patch raises the hard limit of VCPU count to 254. This will allow developers to easily work on scalability and will allow users to test high VCPU setups easily without patching the kernel. To prevent possible issues with current setups, KVM_CAP_NR_VCPUS now returns the recommended VCPU limit (which is still 64) - this should be a safe value for everybody, while a new KVM_CAP_MAX_VCPUS returns the hard limit which is now 254. Cc: Avi Kivity <avi@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Suggested-by:
Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by:
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Sasha Levin authored
Move the check whether there are available entries to within the spinlock. This allows working with larger amount of VCPUs and reduces premature exits when using a large number of VCPUs. Cc: Avi Kivity <avi@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by:
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Xiao Guangrong authored
Using the read/write operation to remove the same code Signed-off-by:
Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by:
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Xiao Guangrong authored
The operations of read emulation and write emulation are very similar, so we can abstract the operation of them, in larter patch, it is used to cleanup the same code Signed-off-by:
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Xiao Guangrong authored
If the range spans a page boundary, the mmio access can be broke, fix it as write emulation. And we already get the guest physical address, so use it to read guest data directly to avoid walking guest page table again Signed-off-by:
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Avi Kivity authored
Src2CL decode (used for double width shifts) erronously decodes only bit 3 of %rcx, instead of bits 7:0. Fix by decoding %cl in its entirety. Signed-off-by:
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