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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-04 09:30:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-04 09:30:33 -0700
commitecefbd94b834fa32559d854646d777c56749ef1c (patch)
treeca8958900ad9e208a8e5fb7704f1b66dc76131b4 /Documentation
parentce57e981f2b996aaca2031003b3f866368307766 (diff)
parent3d11df7abbff013b811d5615320580cd5d9d7d31 (diff)
Merge tag 'kvm-3.7-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Avi Kivity: "Highlights of the changes for this release include support for vfio level triggered interrupts, improved big real mode support on older Intels, a streamlines guest page table walker, guest APIC speedups, PIO optimizations, better overcommit handling, and read-only memory." * tag 'kvm-3.7-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (138 commits) KVM: s390: Fix vcpu_load handling in interrupt code KVM: x86: Fix guest debug across vcpu INIT reset KVM: Add resampling irqfds for level triggered interrupts KVM: optimize apic interrupt delivery KVM: MMU: Eliminate pointless temporary 'ac' KVM: MMU: Avoid access/dirty update loop if all is well KVM: MMU: Eliminate eperm temporary KVM: MMU: Optimize is_last_gpte() KVM: MMU: Simplify walk_addr_generic() loop KVM: MMU: Optimize pte permission checks KVM: MMU: Update accessed and dirty bits after guest pagetable walk KVM: MMU: Move gpte_access() out of paging_tmpl.h KVM: MMU: Optimize gpte_access() slightly KVM: MMU: Push clean gpte write protection out of gpte_access() KVM: clarify kvmclock documentation KVM: make processes waiting on vcpu mutex killable KVM: SVM: Make use of asm.h KVM: VMX: Make use of asm.h KVM: VMX: Make lto-friendly KVM: x86: lapic: Clean up find_highest_vector() and count_vectors() ... Conflicts: arch/s390/include/asm/processor.h arch/x86/kvm/i8259.c
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/virtual/kvm/api.txt33
-rw-r--r--Documentation/virtual/kvm/hypercalls.txt66
-rw-r--r--Documentation/virtual/kvm/msr.txt32
-rw-r--r--Documentation/virtual/kvm/ppc-pv.txt22
4 files changed, 133 insertions, 20 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index bf33aaa4c59f..f6ec3a92e621 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -857,7 +857,8 @@ struct kvm_userspace_memory_region {
};
/* for kvm_memory_region::flags */
-#define KVM_MEM_LOG_DIRTY_PAGES 1UL
+#define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0)
+#define KVM_MEM_READONLY (1UL << 1)
This ioctl allows the user to create or modify a guest physical memory
slot. When changing an existing slot, it may be moved in the guest
@@ -873,14 +874,17 @@ It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr
be identical. This allows large pages in the guest to be backed by large
pages in the host.
-The flags field supports just one flag, KVM_MEM_LOG_DIRTY_PAGES, which
-instructs kvm to keep track of writes to memory within the slot. See
-the KVM_GET_DIRTY_LOG ioctl.
+The flags field supports two flag, KVM_MEM_LOG_DIRTY_PAGES, which instructs
+kvm to keep track of writes to memory within the slot. See KVM_GET_DIRTY_LOG
+ioctl. The KVM_CAP_READONLY_MEM capability indicates the availability of the
+KVM_MEM_READONLY flag. When this flag is set for a memory region, KVM only
+allows read accesses. Writes will be posted to userspace as KVM_EXIT_MMIO
+exits.
-When the KVM_CAP_SYNC_MMU capability, changes in the backing of the memory
-region are automatically reflected into the guest. For example, an mmap()
-that affects the region will be made visible immediately. Another example
-is madvise(MADV_DROP).
+When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of
+the memory region are automatically reflected into the guest. For example, an
+mmap() that affects the region will be made visible immediately. Another
+example is madvise(MADV_DROP).
It is recommended to use this API instead of the KVM_SET_MEMORY_REGION ioctl.
The KVM_SET_MEMORY_REGION does not allow fine grained control over memory
@@ -1946,6 +1950,19 @@ the guest using the specified gsi pin. The irqfd is removed using
the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd
and kvm_irqfd.gsi.
+With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify
+mechanism allowing emulation of level-triggered, irqfd-based
+interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an
+additional eventfd in the kvm_irqfd.resamplefd field. When operating
+in resample mode, posting of an interrupt through kvm_irq.fd asserts
+the specified gsi in the irqchip. When the irqchip is resampled, such
+as from an EOI, the gsi is de-asserted and the user is notifed via
+kvm_irqfd.resamplefd. It is the user's responsibility to re-queue
+the interrupt if the device making use of it still requires service.
+Note that closing the resamplefd is not sufficient to disable the
+irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment
+and need not be specified with KVM_IRQFD_FLAG_DEASSIGN.
+
4.76 KVM_PPC_ALLOCATE_HTAB
Capability: KVM_CAP_PPC_ALLOC_HTAB
diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt
new file mode 100644
index 000000000000..ea113b5d87a4
--- /dev/null
+++ b/Documentation/virtual/kvm/hypercalls.txt
@@ -0,0 +1,66 @@
+Linux KVM Hypercall:
+===================
+X86:
+ KVM Hypercalls have a three-byte sequence of either the vmcall or the vmmcall
+ instruction. The hypervisor can replace it with instructions that are
+ guaranteed to be supported.
+
+ Up to four arguments may be passed in rbx, rcx, rdx, and rsi respectively.
+ The hypercall number should be placed in rax and the return value will be
+ placed in rax. No other registers will be clobbered unless explicitly stated
+ by the particular hypercall.
+
+S390:
+ R2-R7 are used for parameters 1-6. In addition, R1 is used for hypercall
+ number. The return value is written to R2.
+
+ S390 uses diagnose instruction as hypercall (0x500) along with hypercall
+ number in R1.
+
+ PowerPC:
+ It uses R3-R10 and hypercall number in R11. R4-R11 are used as output registers.
+ Return value is placed in R3.
+
+ KVM hypercalls uses 4 byte opcode, that are patched with 'hypercall-instructions'
+ property inside the device tree's /hypervisor node.
+ For more information refer to Documentation/virtual/kvm/ppc-pv.txt
+
+KVM Hypercalls Documentation
+===========================
+The template for each hypercall is:
+1. Hypercall name.
+2. Architecture(s)
+3. Status (deprecated, obsolete, active)
+4. Purpose
+
+1. KVM_HC_VAPIC_POLL_IRQ
+------------------------
+Architecture: x86
+Status: active
+Purpose: Trigger guest exit so that the host can check for pending
+interrupts on reentry.
+
+2. KVM_HC_MMU_OP
+------------------------
+Architecture: x86
+Status: deprecated.
+Purpose: Support MMU operations such as writing to PTE,
+flushing TLB, release PT.
+
+3. KVM_HC_FEATURES
+------------------------
+Architecture: PPC
+Status: active
+Purpose: Expose hypercall availability to the guest. On x86 platforms, cpuid
+used to enumerate which hypercalls are available. On PPC, either device tree
+based lookup ( which is also what EPAPR dictates) OR KVM specific enumeration
+mechanism (which is this hypercall) can be used.
+
+4. KVM_HC_PPC_MAP_MAGIC_PAGE
+------------------------
+Architecture: PPC
+Status: active
+Purpose: To enable communication between the hypervisor and guest there is a
+shared page that contains parts of supervisor visible register state.
+The guest can map this shared page to access its supervisor register through
+memory using this hypercall.
diff --git a/Documentation/virtual/kvm/msr.txt b/Documentation/virtual/kvm/msr.txt
index 730471048583..6d470ae7b073 100644
--- a/Documentation/virtual/kvm/msr.txt
+++ b/Documentation/virtual/kvm/msr.txt
@@ -34,9 +34,12 @@ MSR_KVM_WALL_CLOCK_NEW: 0x4b564d00
time information and check that they are both equal and even.
An odd version indicates an in-progress update.
- sec: number of seconds for wallclock.
+ sec: number of seconds for wallclock at time of boot.
- nsec: number of nanoseconds for wallclock.
+ nsec: number of nanoseconds for wallclock at time of boot.
+
+ In order to get the current wallclock time, the system_time from
+ MSR_KVM_SYSTEM_TIME_NEW needs to be added.
Note that although MSRs are per-CPU entities, the effect of this
particular MSR is global.
@@ -82,20 +85,25 @@ MSR_KVM_SYSTEM_TIME_NEW: 0x4b564d01
time at the time this structure was last updated. Unit is
nanoseconds.
- tsc_to_system_mul: a function of the tsc frequency. One has
- to multiply any tsc-related quantity by this value to get
- a value in nanoseconds, besides dividing by 2^tsc_shift
+ tsc_to_system_mul: multiplier to be used when converting
+ tsc-related quantity to nanoseconds
- tsc_shift: cycle to nanosecond divider, as a power of two, to
- allow for shift rights. One has to shift right any tsc-related
- quantity by this value to get a value in nanoseconds, besides
- multiplying by tsc_to_system_mul.
+ tsc_shift: shift to be used when converting tsc-related
+ quantity to nanoseconds. This shift will ensure that
+ multiplication with tsc_to_system_mul does not overflow.
+ A positive value denotes a left shift, a negative value
+ a right shift.
- With this information, guests can derive per-CPU time by
- doing:
+ The conversion from tsc to nanoseconds involves an additional
+ right shift by 32 bits. With this information, guests can
+ derive per-CPU time by doing:
time = (current_tsc - tsc_timestamp)
- time = (time * tsc_to_system_mul) >> tsc_shift
+ if (tsc_shift >= 0)
+ time <<= tsc_shift;
+ else
+ time >>= -tsc_shift;
+ time = (time * tsc_to_system_mul) >> 32
time = time + system_time
flags: bits in this field indicate extended capabilities
diff --git a/Documentation/virtual/kvm/ppc-pv.txt b/Documentation/virtual/kvm/ppc-pv.txt
index 4911cf95c67e..4cd076febb02 100644
--- a/Documentation/virtual/kvm/ppc-pv.txt
+++ b/Documentation/virtual/kvm/ppc-pv.txt
@@ -174,3 +174,25 @@ following:
That way we can inject an arbitrary amount of code as replacement for a single
instruction. This allows us to check for pending interrupts when setting EE=1
for example.
+
+Hypercall ABIs in KVM on PowerPC
+=================================
+1) KVM hypercalls (ePAPR)
+
+These are ePAPR compliant hypercall implementation (mentioned above). Even
+generic hypercalls are implemented here, like the ePAPR idle hcall. These are
+available on all targets.
+
+2) PAPR hypercalls
+
+PAPR hypercalls are needed to run server PowerPC PAPR guests (-M pseries in QEMU).
+These are the same hypercalls that pHyp, the POWER hypervisor implements. Some of
+them are handled in the kernel, some are handled in user space. This is only
+available on book3s_64.
+
+3) OSI hypercalls
+
+Mac-on-Linux is another user of KVM on PowerPC, which has its own hypercall (long
+before KVM). This is supported to maintain compatibility. All these hypercalls get
+forwarded to user space. This is only useful on book3s_32, but can be used with
+book3s_64 as well.