- 16 7月, 2007 9 次提交
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由 Avi Kivity 提交于
This prevents some work from being performed twice, and, more importantly, reduces the number of places where we modify shadow ptes. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
We will need the accessed bit (in addition to the dirty bit) and also write access (for setting the dirty bit) in a future patch. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
In preparation of some modifications. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Eddie Dong 提交于
Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
Simpifies things a bit. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
A typical demand page/copy on write pattern is: - page fault on vaddr - kvm propagates fault to guest - guest handles fault, updates pte - kvm traps write, clears shadow pte, resumes guest - guest returns to userspace, re-faults on same vaddr - kvm installs shadow pte, resumes guest - guest continues So, three vmexits for a single guest page fault. But if instead of clearing the page table entry, we update to correspond to the value that the guest has just written, we eliminate the third vmexit. This patch does exactly that, reducing kbuild time by about 10%. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
The kvm mmu tries to detects forks by looking for repeated writes to a page table. If it sees a fork, it unshadows the page table so the page table copying can proceed at native speed instead of being emulated. However, the detector also triggered on simple demand paging access patterns: a linear walk of memory would of course cause repeated writes to the same pagetable page, causing it to unshadow prematurely. Fix by resetting the fork detector if we detect a demand fault. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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- 03 5月, 2007 3 次提交
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由 Avi Kivity 提交于
Make the exit statistics per-vcpu instead of global. This gives a 3.5% boost when running one virtual machine per core on my two socket dual core (4 cores total) machine. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
The kvm mmu keeps a shadow page for hugepage pdes; if several such pdes map the same physical address, they share the same shadow page. This is a fairly common case (kernel mappings on i386 nonpae Linux, for example). However, if the two pdes map the same memory but with different permissions, kvm will happily use the cached shadow page. If the access through the more permissive pde will occur after the access to the strict pde, an endless pagefault loop will be generated and the guest will make no progress. Fix by making the access permissions part of the cache lookup key. The fix allows Xen pae to boot on kvm and run guest domains. Thanks to Jeremy Fitzhardinge for reporting the bug and testing the fix. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
We already special case the pdptr access, so no need to check it again. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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- 04 3月, 2007 2 次提交
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由 Avi Kivity 提交于
Signed-off-by: NAvi Kivity <avi@qumranet.com>
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由 Avi Kivity 提交于
We fail to mark a page dirty in three cases: - setting the accessed bit in a pte - setting the dirty bit in a pte - emulating a write into a pagetable This fix adds the missing cases. Signed-off-by: NAvi Kivity <avi@qumranet.com>
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- 13 2月, 2007 1 次提交
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由 Avi Kivity 提交于
gva_to_gpa() needs to be updated to the new walk_addr() calling convention, otherwise it may oops under some circumstances. Use the opportunity to remove all the code duplication in gva_to_gpa(), which essentially repeats the calculations in walk_addr(). Signed-off-by: NAvi Kivity <avi@qumranet.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 1月, 2007 2 次提交
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由 Avi Kivity 提交于
With the recent guest page fault change, we perform access checks on our own instead of relying on the cpu. This means we have to perform the nx checks as well. Software like the google toolbar on windows appears to rely on this somehow. Signed-off-by: NAvi Kivity <avi@qumranet.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Avi Kivity 提交于
Check pte permission bits in walk_addr(), instead of scattering the checks all over the code. This has the following benefits: 1. We no longer set the accessed bit for accessed which fail permission checks. 2. Setting the accessed bit is simplified. 3. Under some circumstances, we used to pretend a page fault was fixed when it would actually fail the access checks. This caused an unnecessary vmexit. 4. The error code for guest page faults is now correct. The fix helps netbsd further along booting, and allows kvm to pass the new mmu testsuite. Signed-off-by: NAvi Kivity <avi@qumranet.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 23 1月, 2007 1 次提交
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由 Avi Kivity 提交于
If a page is marked as dirty in the guest pte, set_pte_common() can set the writable bit on newly-instantiated shadow pte. This optimization avoids a write fault after the initial read fault. However, if a write fault instantiates the pte, fix_write_pf() incorrectly reports the fault as a guest page fault, and the guest oopses on what appears to be a correctly-mapped page. Fix is to detect the condition and only report a guest page fault on a user access to a kernel page. With the fix, a kvm guest can survive a whole night of running the kernel hacker's screensaver (make -j9 in a loop). Signed-off-by: NAvi Kivity <avi@qumranet.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 06 1月, 2007 15 次提交
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由 Avi Kivity 提交于
If we emulate a write, we fail to set the dirty bit on the guest pte, leading the guest to believe the page is clean, and thus lose data. Bad. Fix by setting the guest pte dirty bit under such conditions. Signed-off-by: NAvi Kivity <avi@qumranet.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
The mmu sometimes needs memory for reverse mapping and parent pte chains. however, we can't allocate from within the mmu because of the atomic context. So, move the allocations to a central place that can be executed before the main mmu machinery, where we can bail out on failure before any damage is done. (error handling is deffered for now, but the basic structure is there) Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
When beginning to process a page fault, make sure we have enough shadow pages available to service the fault. If not, free some pages. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
This fixes a problem where set_pte_common() looked for shadowed pages based on the page directory gfn (a huge page) instead of the actual gfn being mapped. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
When we cache a guest page table into a shadow page table, we need to prevent further access to that page by the guest, as that would render the cache incoherent. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
Define a hashtable for caching shadow page tables. Look up the cache on context switch (cr3 change) or during page faults. The key to the cache is a combination of - the guest page table frame number - the number of paging levels in the guest * we can cache real mode, 32-bit mode, pae, and long mode page tables simultaneously. this is useful for smp bootup. - the guest page table table * some kernels use a page as both a page table and a page directory. this allows multiple shadow pages to exist for that page, one per level - the "quadrant" * 32-bit mode page tables span 4MB, whereas a shadow page table spans 2MB. similarly, a 32-bit page directory spans 4GB, while a shadow page directory spans 1GB. the quadrant allows caching up to 4 shadow page tables for one guest page in one level. - a "metaphysical" bit * for real mode, and for pse pages, there is no guest page table, so set the bit to avoid write protecting the page. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
This allows further manipulation on the shadow page table. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
This lets us not write protect a partial page, and is anyway what a real processor does. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
It is never necessary to fetch a guest entry from an intermediate page table level (except for large pages), so avoid some confusion by always descending into the lowest possible level. Rename init_walker() to walk_addr() as it is no longer restricted to initialization. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
Saving the table gfns removes the need to walk the guest and host page tables in lockstep. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Avi Kivity 提交于
Keep in each host page frame's page->private a pointer to the shadow pte which maps it. If there are multiple shadow ptes mapping the page, set bit 0 of page->private, and use the rest as a pointer to a linked list of all such mappings. Reverse mappings are needed because we when we cache shadow page tables, we must protect the guest page tables from being modified by the guest, as that would invalidate the cached ptes. Signed-off-by: NAvi Kivity <avi@qumranet.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 31 12月, 2006 1 次提交
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由 Avi Kivity 提交于
Instead of doing tricky stuff with the arch dependent virtualization registers, take a peek at the guest's efer. This simlifies some code, and fixes some confusion in the mmu branch. Signed-off-by: NAvi Kivity <avi@qumranet.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 14 12月, 2006 1 次提交
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由 Avi Kivity 提交于
The pcd, pwt, and pat bits on page table entries affect the cpu cache. Since the cache is a host resource, the guest should not be able to control it. Moreover, the meaning of these bits changes depending on whether pat is enabled or not. So, force these bits to zero on shadow page table entries at all times. Signed-off-by: NAvi Kivity <avi@qumranet.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 11 12月, 2006 1 次提交
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由 Avi Kivity 提交于
web site: http://kvm.sourceforge.net mailing list: kvm-devel@lists.sourceforge.net (http://lists.sourceforge.net/lists/listinfo/kvm-devel) The following patchset adds a driver for Intel's hardware virtualization extensions to the x86 architecture. The driver adds a character device (/dev/kvm) that exposes the virtualization capabilities to userspace. Using this driver, a process can run a virtual machine (a "guest") in a fully virtualized PC containing its own virtual hard disks, network adapters, and display. Using this driver, one can start multiple virtual machines on a host. Each virtual machine is a process on the host; a virtual cpu is a thread in that process. kill(1), nice(1), top(1) work as expected. In effect, the driver adds a third execution mode to the existing two: we now have kernel mode, user mode, and guest mode. Guest mode has its own address space mapping guest physical memory (which is accessible to user mode by mmap()ing /dev/kvm). Guest mode has no access to any I/O devices; any such access is intercepted and directed to user mode for emulation. The driver supports i386 and x86_64 hosts and guests. All combinations are allowed except x86_64 guest on i386 host. For i386 guests and hosts, both pae and non-pae paging modes are supported. SMP hosts and UP guests are supported. At the moment only Intel hardware is supported, but AMD virtualization support is being worked on. Performance currently is non-stellar due to the naive implementation of the mmu virtualization, which throws away most of the shadow page table entries every context switch. We plan to address this in two ways: - cache shadow page tables across tlb flushes - wait until AMD and Intel release processors with nested page tables Currently a virtual desktop is responsive but consumes a lot of CPU. Under Windows I tried playing pinball and watching a few flash movies; with a recent CPU one can hardly feel the virtualization. Linux/X is slower, probably due to X being in a separate process. In addition to the driver, you need a slightly modified qemu to provide I/O device emulation and the BIOS. Caveats (akpm: might no longer be true): - The Windows install currently bluescreens due to a problem with the virtual APIC. We are working on a fix. A temporary workaround is to use an existing image or install through qemu - Windows 64-bit does not work. That's also true for qemu, so it's probably a problem with the device model. [bero@arklinux.org: build fix] [simon.kagstrom@bth.se: build fix, other fixes] [uril@qumranet.com: KVM: Expose interrupt bitmap] [akpm@osdl.org: i386 build fix] [mingo@elte.hu: i386 fixes] [rdreier@cisco.com: add log levels to all printks] [randy.dunlap@oracle.com: Fix sparse NULL and C99 struct init warnings] [anthony@codemonkey.ws: KVM: AMD SVM: 32-bit host support] Signed-off-by: NYaniv Kamay <yaniv@qumranet.com> Signed-off-by: NAvi Kivity <avi@qumranet.com> Cc: Simon Kagstrom <simon.kagstrom@bth.se> Cc: Bernhard Rosenkraenzer <bero@arklinux.org> Signed-off-by: NUri Lublin <uril@qumranet.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAnthony Liguori <anthony@codemonkey.ws> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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