diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-28 15:40:51 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-28 15:40:51 -0700 |
commit | 36824f198c621cebeb22966b5e244378fa341295 (patch) | |
tree | ee1e358a4ed0cd022ae12b4b7ba1fa3d0e5746d5 /virt/kvm/binary_stats.c | |
parent | 9840cfcb97fc8b6aa7b36cec3cc3fd763f14052e (diff) | |
parent | b8917b4ae44d1b945f6fba3d8ee6777edb44633b (diff) |
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"This covers all architectures (except MIPS) so I don't expect any
other feature pull requests this merge window.
ARM:
- Add MTE support in guests, complete with tag save/restore interface
- Reduce the impact of CMOs by moving them in the page-table code
- Allow device block mappings at stage-2
- Reduce the footprint of the vmemmap in protected mode
- Support the vGIC on dumb systems such as the Apple M1
- Add selftest infrastructure to support multiple configuration and
apply that to PMU/non-PMU setups
- Add selftests for the debug architecture
- The usual crop of PMU fixes
PPC:
- Support for the H_RPT_INVALIDATE hypercall
- Conversion of Book3S entry/exit to C
- Bug fixes
S390:
- new HW facilities for guests
- make inline assembly more robust with KASAN and co
x86:
- Allow userspace to handle emulation errors (unknown instructions)
- Lazy allocation of the rmap (host physical -> guest physical
address)
- Support for virtualizing TSC scaling on VMX machines
- Optimizations to avoid shattering huge pages at the beginning of
live migration
- Support for initializing the PDPTRs without loading them from
memory
- Many TLB flushing cleanups
- Refuse to load if two-stage paging is available but NX is not (this
has been a requirement in practice for over a year)
- A large series that separates the MMU mode (WP/SMAP/SMEP etc.) from
CR0/CR4/EFER, using the MMU mode everywhere once it is computed
from the CPU registers
- Use PM notifier to notify the guest about host suspend or hibernate
- Support for passing arguments to Hyper-V hypercalls using XMM
registers
- Support for Hyper-V TLB flush hypercalls and enlightened MSR bitmap
on AMD processors
- Hide Hyper-V hypercalls that are not included in the guest CPUID
- Fixes for live migration of virtual machines that use the Hyper-V
"enlightened VMCS" optimization of nested virtualization
- Bugfixes (not many)
Generic:
- Support for retrieving statistics without debugfs
- Cleanups for the KVM selftests API"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (314 commits)
KVM: x86: rename apic_access_page_done to apic_access_memslot_enabled
kvm: x86: disable the narrow guest module parameter on unload
selftests: kvm: Allows userspace to handle emulation errors.
kvm: x86: Allow userspace to handle emulation errors
KVM: x86/mmu: Let guest use GBPAGES if supported in hardware and TDP is on
KVM: x86/mmu: Get CR4.SMEP from MMU, not vCPU, in shadow page fault
KVM: x86/mmu: Get CR0.WP from MMU, not vCPU, in shadow page fault
KVM: x86/mmu: Drop redundant rsvd bits reset for nested NPT
KVM: x86/mmu: Optimize and clean up so called "last nonleaf level" logic
KVM: x86: Enhance comments for MMU roles and nested transition trickiness
KVM: x86/mmu: WARN on any reserved SPTE value when making a valid SPTE
KVM: x86/mmu: Add helpers to do full reserved SPTE checks w/ generic MMU
KVM: x86/mmu: Use MMU's role to determine PTTYPE
KVM: x86/mmu: Collapse 32-bit PAE and 64-bit statements for helpers
KVM: x86/mmu: Add a helper to calculate root from role_regs
KVM: x86/mmu: Add helper to update paging metadata
KVM: x86/mmu: Don't update nested guest's paging bitmasks if CR0.PG=0
KVM: x86/mmu: Consolidate reset_rsvds_bits_mask() calls
KVM: x86/mmu: Use MMU role_regs to get LA57, and drop vCPU LA57 helper
KVM: x86/mmu: Get nested MMU's root level from the MMU's role
...
Diffstat (limited to 'virt/kvm/binary_stats.c')
-rw-r--r-- | virt/kvm/binary_stats.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/virt/kvm/binary_stats.c b/virt/kvm/binary_stats.c new file mode 100644 index 000000000000..e609d428811a --- /dev/null +++ b/virt/kvm/binary_stats.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * KVM binary statistics interface implementation + * + * Copyright 2021 Google LLC + */ + +#include <linux/kvm_host.h> +#include <linux/kvm.h> +#include <linux/errno.h> +#include <linux/uaccess.h> + +/** + * kvm_stats_read() - Common function to read from the binary statistics + * file descriptor. + * + * @id: identification string of the stats + * @header: stats header for a vm or a vcpu + * @desc: start address of an array of stats descriptors for a vm or a vcpu + * @stats: start address of stats data block for a vm or a vcpu + * @size_stats: the size of stats data block pointed by @stats + * @user_buffer: start address of userspace buffer + * @size: requested read size from userspace + * @offset: the start position from which the content will be read for the + * corresponding vm or vcp file descriptor + * + * The file content of a vm/vcpu file descriptor is now defined as below: + * +-------------+ + * | Header | + * +-------------+ + * | id string | + * +-------------+ + * | Descriptors | + * +-------------+ + * | Stats Data | + * +-------------+ + * Although this function allows userspace to read any amount of data (as long + * as in the limit) from any position, the typical usage would follow below + * steps: + * 1. Read header from offset 0. Get the offset of descriptors and stats data + * and some other necessary information. This is a one-time work for the + * lifecycle of the corresponding vm/vcpu stats fd. + * 2. Read id string from its offset. This is a one-time work for the lifecycle + * of the corresponding vm/vcpu stats fd. + * 3. Read descriptors from its offset and discover all the stats by parsing + * descriptors. This is a one-time work for the lifecycle of the + * corresponding vm/vcpu stats fd. + * 4. Periodically read stats data from its offset using pread. + * + * Return: the number of bytes that has been successfully read + */ +ssize_t kvm_stats_read(char *id, const struct kvm_stats_header *header, + const struct _kvm_stats_desc *desc, + void *stats, size_t size_stats, + char __user *user_buffer, size_t size, loff_t *offset) +{ + ssize_t len; + ssize_t copylen; + ssize_t remain = size; + size_t size_desc; + size_t size_header; + void *src; + loff_t pos = *offset; + char __user *dest = user_buffer; + + size_header = sizeof(*header); + size_desc = header->num_desc * sizeof(*desc); + + len = KVM_STATS_NAME_SIZE + size_header + size_desc + size_stats - pos; + len = min(len, remain); + if (len <= 0) + return 0; + remain = len; + + /* + * Copy kvm stats header. + * The header is the first block of content userspace usually read out. + * The pos is 0 and the copylen and remain would be the size of header. + * The copy of the header would be skipped if offset is larger than the + * size of header. That usually happens when userspace reads stats + * descriptors and stats data. + */ + copylen = size_header - pos; + copylen = min(copylen, remain); + if (copylen > 0) { + src = (void *)header + pos; + if (copy_to_user(dest, src, copylen)) + return -EFAULT; + remain -= copylen; + pos += copylen; + dest += copylen; + } + + /* + * Copy kvm stats header id string. + * The id string is unique for every vm/vcpu, which is stored in kvm + * and kvm_vcpu structure. + * The id string is part of the stat header from the perspective of + * userspace, it is usually read out together with previous constant + * header part and could be skipped for later descriptors and stats + * data readings. + */ + copylen = header->id_offset + KVM_STATS_NAME_SIZE - pos; + copylen = min(copylen, remain); + if (copylen > 0) { + src = id + pos - header->id_offset; + if (copy_to_user(dest, src, copylen)) + return -EFAULT; + remain -= copylen; + pos += copylen; + dest += copylen; + } + + /* + * Copy kvm stats descriptors. + * The descriptors copy would be skipped in the typical case that + * userspace periodically read stats data, since the pos would be + * greater than the end address of descriptors + * (header->header.desc_offset + size_desc) causing copylen <= 0. + */ + copylen = header->desc_offset + size_desc - pos; + copylen = min(copylen, remain); + if (copylen > 0) { + src = (void *)desc + pos - header->desc_offset; + if (copy_to_user(dest, src, copylen)) + return -EFAULT; + remain -= copylen; + pos += copylen; + dest += copylen; + } + + /* Copy kvm stats values */ + copylen = header->data_offset + size_stats - pos; + copylen = min(copylen, remain); + if (copylen > 0) { + src = stats + pos - header->data_offset; + if (copy_to_user(dest, src, copylen)) + return -EFAULT; + remain -= copylen; + pos += copylen; + dest += copylen; + } + + *offset = pos; + return len; +} |