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2023-10-09KVM: x86/mmu: Zap SPTEs on MTRR update iff guest MTRRs are honoredYan Zhao
When guest MTRRs are updated, zap SPTEs and do zap range calcluation if and only if KVM's MMU is honoring guest MTRRs, which is the only time that KVM incorporates the guest's MTRR type into the final memtype. Suggested-by: Chao Gao <chao.gao@intel.com> Suggested-by: Sean Christopherson <seanjc@google.com> Cc: Kai Huang <kai.huang@intel.com> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com> Link: https://lore.kernel.org/r/20230714065156.20375-1-yan.y.zhao@intel.com [sean: rephrase shortlog] Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-01KVM: x86: Make kvm_mtrr_valid() static now that there are no external usersSean Christopherson
Make kvm_mtrr_valid() local to mtrr.c now that it's not used to check the validity of a PAT MSR value. Reviewed-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/r/20230511233351.635053-8-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-01KVM: x86: Move PAT MSR handling out of mtrr.cSean Christopherson
Drop handling of MSR_IA32_CR_PAT from mtrr.c now that SVM and VMX handle writes without bouncing through kvm_set_msr_common(). PAT isn't truly an MTRR even though it affects memory types, and more importantly KVM enables hardware virtualization of guest PAT (by NOT setting "ignore guest PAT") when a guest has non-coherent DMA, i.e. KVM doesn't need to zap SPTEs when the guest PAT changes. The read path is and always has been trivial, i.e. burying it in the MTRR code does more harm than good. WARN and continue for the PAT case in kvm_set_msr_common(), as that code is _currently_ reached if and only if KVM is buggy. Defer cleaning up the lack of symmetry between the read and write paths to a future patch. Reviewed-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/r/20230511233351.635053-7-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-01KVM: x86: Use MTRR macros to define possible MTRR MSR rangesSean Christopherson
Use the MTRR macros to identify the ranges of possible MTRR MSRs instead of bounding the ranges with a mismash of open coded values and unrelated MSR indices. Carving out the gap for the machine check MSRs in particular is confusing, as it's easy to incorrectly think the case statement handles MCE MSRs instead of skipping them. Drop the range-based funneling of MSRs between the end of the MCE MSRs and MTRR_DEF_TYPE, i.e. 0x2A0-0x2FF, and instead handle MTTR_DEF_TYPE as the one-off case that it is. Extract PAT (0x277) as well in anticipation of dropping PAT "handling" from the MTRR code. Keep the range-based handling for the variable+fixed MTRRs even though capturing unknown MSRs 0x214-0x24F is arguably "wrong". There is a gap in the fixed MTRRs, 0x260-0x267, i.e. the MTRR code needs to filter out unknown MSRs anyways, and using a single range generates marginally better code for the big switch statement. Reviewed-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/r/20230511233351.635053-6-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-01KVM: x86: Add helper to get variable MTRR range from MSR indexSean Christopherson
Add a helper to dedup the logic for retrieving a variable MTRR range structure given a variable MTRR MSR index. No functional change intended. Reviewed-by: Kai Huang <kai.huang@intel.com> Link: https://lore.kernel.org/r/20230511233351.635053-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-01KVM: x86: Add helper to query if variable MTRR MSR is base (versus mask)Sean Christopherson
Add a helper to query whether a variable MTRR MSR is a base versus as mask MSR. Replace the unnecessarily complex math with a simple check on bit 0; base MSRs are even, mask MSRs are odd. Link: https://lore.kernel.org/r/20230511233351.635053-4-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-12-29KVM: x86: Unify pr_fmt to use module name for all KVM modulesSean Christopherson
Define pr_fmt using KBUILD_MODNAME for all KVM x86 code so that printks use consistent formatting across common x86, Intel, and AMD code. In addition to providing consistent print formatting, using KBUILD_MODNAME, e.g. kvm_amd and kvm_intel, allows referencing SVM and VMX (and SEV and SGX and ...) as technologies without generating weird messages, and without causing naming conflicts with other kernel code, e.g. "SEV: ", "tdx: ", "sgx: " etc.. are all used by the kernel for non-KVM subsystems. Opportunistically move away from printk() for prints that need to be modified anyways, e.g. to drop a manual "kvm: " prefix. Opportunistically convert a few SGX WARNs that are similarly modified to WARN_ONCE; in the very unlikely event that the WARNs fire, odds are good that they would fire repeatedly and spam the kernel log without providing unique information in each print. Note, defining pr_fmt yields undesirable results for code that uses KVM's printk wrappers, e.g. vcpu_unimpl(). But, that's a pre-existing problem as SVM/kvm_amd already defines a pr_fmt, and thankfully use of KVM's wrappers is relatively limited in KVM x86 code. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Paul Durrant <paul@xen.org> Message-Id: <20221130230934.1014142-35-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: x86: Add helper to consolidate "raw" reserved GPA mask calculationsSean Christopherson
Add a helper to generate the mask of reserved GPA bits _without_ any adjustments for repurposed bits, and use it to replace a variety of open coded variants in the MTRR and APIC_BASE flows. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210204000117.3303214-11-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-15KVM: x86: remove bogus #GP injectionPaolo Bonzini
There is no need to inject a #GP from kvm_mtrr_set_msr, kvm_emulate_wrmsr will handle it. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27KVM: x86: Protect MSR-based index computations in fixed_msr_to_seg_unit() ↵Marios Pomonis
from Spectre-v1/L1TF attacks This fixes a Spectre-v1/L1TF vulnerability in fixed_msr_to_seg_unit(). This function contains index computations based on the (attacker-controlled) MSR number. Fixes: de9aef5e1ad6 ("KVM: MTRR: introduce fixed_mtrr_segment table") Signed-off-by: Nick Finco <nifi@google.com> Signed-off-by: Marios Pomonis <pomonis@google.com> Reviewed-by: Andrew Honig <ahonig@google.com> Cc: stable@vger.kernel.org Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499Thomas Gleixner
Based on 1 normalized pattern(s): this work is licensed under the terms of the gnu gpl version 2 see the copying file in the top level directory extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 35 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-16KVM: x86: optimize check for valid PAT valuePaolo Bonzini
This check will soon be done on every nested vmentry and vmexit, "parallelize" it using bitwise operations. Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-07KVM: x86: generalize guest_cpuid_has_ helpersRadim Krčmář
This patch turns guest_cpuid_has_XYZ(cpuid) into guest_cpuid_has(cpuid, X86_FEATURE_XYZ), which gets rid of many very similar helpers. When seeing a X86_FEATURE_*, we can know which cpuid it belongs to, but this information isn't in common code, so we recreate it for KVM. Add some BUILD_BUG_ONs to make sure that it runs nicely. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-05KVM: MTRR: fix kvm_mtrr_check_gfn_range_consistency page faultAlexis Dambricourt
The following #PF may occurs: [ 1403.317041] BUG: unable to handle kernel paging request at 0000000200000068 [ 1403.317045] IP: [<ffffffffc04c20b0>] __mtrr_lookup_var_next+0x10/0xa0 [kvm] [ 1403.317123] Call Trace: [ 1403.317134] [<ffffffffc04c2a65>] ? kvm_mtrr_check_gfn_range_consistency+0xc5/0x120 [kvm] [ 1403.317143] [<ffffffffc04ac11f>] ? tdp_page_fault+0x9f/0x2c0 [kvm] [ 1403.317152] [<ffffffffc0498128>] ? kvm_set_msr_common+0x858/0xc00 [kvm] [ 1403.317161] [<ffffffffc04b8883>] ? x86_emulate_insn+0x273/0xd30 [kvm] [ 1403.317171] [<ffffffffc04c04e4>] ? kvm_cpuid+0x34/0x190 [kvm] [ 1403.317180] [<ffffffffc04a5bb9>] ? kvm_mmu_page_fault+0x59/0xe0 [kvm] [ 1403.317183] [<ffffffffc0d729e1>] ? vmx_handle_exit+0x1d1/0x14a0 [kvm_intel] [ 1403.317185] [<ffffffffc0d75f3f>] ? atomic_switch_perf_msrs+0x6f/0xa0 [kvm_intel] [ 1403.317187] [<ffffffffc0d7621d>] ? vmx_vcpu_run+0x2ad/0x420 [kvm_intel] [ 1403.317196] [<ffffffffc04a0962>] ? kvm_arch_vcpu_ioctl_run+0x622/0x1550 [kvm] [ 1403.317204] [<ffffffffc049abb9>] ? kvm_arch_vcpu_load+0x59/0x210 [kvm] [ 1403.317206] [<ffffffff81036245>] ? __kernel_fpu_end+0x35/0x100 [ 1403.317213] [<ffffffffc0487eb6>] ? kvm_vcpu_ioctl+0x316/0x5d0 [kvm] [ 1403.317215] [<ffffffff81088225>] ? do_sigtimedwait+0xd5/0x220 [ 1403.317217] [<ffffffff811f84dd>] ? do_vfs_ioctl+0x9d/0x5c0 [ 1403.317224] [<ffffffffc04928ae>] ? kvm_on_user_return+0x3e/0x70 [kvm] [ 1403.317225] [<ffffffff811f8a74>] ? SyS_ioctl+0x74/0x80 [ 1403.317227] [<ffffffff815bf0b6>] ? entry_SYSCALL_64_fastpath+0x1e/0xa8 [ 1403.317242] RIP [<ffffffffc04c20b0>] __mtrr_lookup_var_next+0x10/0xa0 [kvm] At mtrr_lookup_fixed_next(), when the condition 'if (iter->index >= ARRAY_SIZE(iter->mtrr_state->fixed_ranges))' becomes true, mtrr_lookup_var_start() is called with iter->range with gargabe values from the fixed MTRR union field. Then, list_prepare_entry() do not call list_entry() initialization, keeping a garbage pointer in iter->range which is accessed in the following __mtrr_lookup_var_next() call. Fixes: f571c0973e4b8c888e049b6842e4b4f93b5c609c Signed-off-by: Alexis Dambricourt <alexis@blade-group.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-18KVM: MTRR: remove MSR 0x2f8Andy Honig
MSR 0x2f8 accessed the 124th Variable Range MTRR ever since MTRR support was introduced by 9ba075a664df ("KVM: MTRR support"). 0x2f8 became harmful when 910a6aae4e2e ("KVM: MTRR: exactly define the size of variable MTRRs") shrinked the array of VR MTRRs from 256 to 8, which made access to index 124 out of bounds. The surrounding code only WARNs in this situation, thus the guest gained a limited read/write access to struct kvm_arch_vcpu. 0x2f8 is not a valid VR MTRR MSR, because KVM has/advertises only 16 VR MTRR MSRs, 0x200-0x20f. Every VR MTRR is set up using two MSRs, 0x2f8 was treated as a PHYSBASE and 0x2f9 would be its PHYSMASK, but 0x2f9 was not implemented in KVM, therefore 0x2f8 could never do anything useful and getting rid of it is safe. This fixes CVE-2016-3713. Fixes: 910a6aae4e2e ("KVM: MTRR: exactly define the size of variable MTRRs") Cc: stable@vger.kernel.org Reported-by: David Matlack <dmatlack@google.com> Signed-off-by: Andy Honig <ahonig@google.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-12-22KVM: MTRR: treat memory as writeback if MTRR is disabled in guest CPUIDPaolo Bonzini
Virtual machines can be run with CPUID such that there are no MTRRs. In that case, the firmware will never enable MTRRs and it is obviously undesirable to run the guest entirely with UC memory. Check out guest CPUID, and use WB memory if MTRR do not exist. Cc: qemu-stable@nongnu.org Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107561 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-12-22KVM: MTRR: observe maxphyaddr from guest CPUID, not hostPaolo Bonzini
Conversion of MTRRs to ranges used the maxphyaddr from the boot CPU. This is wrong, because var_mtrr_range's mask variable then is discontiguous (like FF00FFFF000, where the first run of 0s corresponds to the bits between host and guest maxphyaddr). Instead always set up the masks to be full 64-bit values---we know that the reserved bits at the top are zero, and we can restore them when reading the MSR. This way var_mtrr_range gets a mask that just works. Fixes: a13842dc668b40daef4327294a6d3bdc8bd30276 Cc: qemu-stable@nongnu.org Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107561 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-12-22KVM: MTRR: fix fixed MTRR segment look upAlexis Dambricourt
This fixes the slow-down of VM running with pci-passthrough, since some MTRR range changed from MTRR_TYPE_WRBACK to MTRR_TYPE_UNCACHABLE. Memory in the 0K-640K range was incorrectly treated as uncacheable. Fixes: f7bfb57b3e89ff89c0da9f93dedab89f68d6ca27 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107561 Cc: qemu-stable@nongnu.org Signed-off-by: Alexis Dambricourt <alexis.dambricourt@gmail.com> [Use correct BZ for "Fixes" annotation. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-08-05KVM: MTRR: Use default type for non-MTRR-covered gfn before WARN_ONAlex Williamson
The patch was munged on commit to re-order these tests resulting in excessive warnings when trying to do device assignment. Return to original ordering: https://lkml.org/lkml/2015/7/15/769 Fixes: 3e5d2fdceda1 ("KVM: MTRR: simplify kvm_mtrr_get_guest_memory_type") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-07-23KVM: MTRR: simplify kvm_mtrr_get_guest_memory_typeXiao Guangrong
kvm_mtrr_get_guest_memory_type never returns -1 which is implied in the current code since if @type = -1 (means no MTRR contains the range), iter.partial_map must be true Simplify the code to indicate this fact Signed-off-by: Xiao Guangrong <guangrong.xiao@intel.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-07-23KVM: MTRR: fix memory type handling if MTRR is completely disabledXiao Guangrong
Currently code uses default memory type if MTRR is fully disabled, fix it by using UC instead. Signed-off-by: Xiao Guangrong <guangrong.xiao@intel.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: do not map huge page for non-consistent rangeXiao Guangrong
Based on Intel's SDM, mapping huge page which do not have consistent memory cache for each 4k page will cause undefined behavior In order to avoiding this kind of undefined behavior, we force to use 4k pages under this case Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: simplify kvm_mtrr_get_guest_memory_typeXiao Guangrong
mtrr_for_each_mem_type() is ready now, use it to simplify kvm_mtrr_get_guest_memory_type() Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: introduce mtrr_for_each_mem_typeXiao Guangrong
It walks all MTRRs and gets all the memory cache type setting for the specified range also it checks if the range is fully covered by MTRRs Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> [Adjust for range_size->range_shift change. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: introduce fixed_mtrr_addr_* functionsXiao Guangrong
Two functions are introduced: - fixed_mtrr_addr_to_seg() translates the address to the fixed MTRR segment - fixed_mtrr_addr_seg_to_range_index() translates the address to the index of kvm_mtrr.fixed_ranges[] They will be used in the later patch Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> [Adjust for range_size->range_shift change. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: sort variable MTRRsXiao Guangrong
Sort all valid variable MTRRs based on its base address, it will help us to check a range to see if it's fully contained in variable MTRRs Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> [Fix list insertion sort, simplify var_mtrr_range_is_valid to just test the V bit. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: introduce var_mtrr_rangeXiao Guangrong
It gets the range for the specified variable MTRR Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> [Simplify boolean operations. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: introduce fixed_mtrr_segment tableXiao Guangrong
This table summarizes the information of fixed MTRRs and introduce some APIs to abstract its operation which helps us to clean up the code and will be used in later patches Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> [Change range_size to range_shift, in order to avoid udivdi3 errors. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: improve kvm_mtrr_get_guest_memory_typeXiao Guangrong
- kvm_mtrr_get_guest_memory_type() only checks one page in MTRRs so that it's unnecessary to check to see if the range is partially covered in MTRR - optimize the check of overlap memory type and add some comments to explain the precedence Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: do not split 64 bits MSR contentXiao Guangrong
Variable MTRR MSRs are 64 bits which are directly accessed with full length, no reason to split them to two 32 bits Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: clean up mtrr default typeXiao Guangrong
Drop kvm_mtrr->enable, omit the decode/code workload and get rid of all the hard code Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: remove mtrr_state.have_fixedXiao Guangrong
vMTRR does not depend on any host MTRR feature and fixed MTRRs have always been implemented, so drop this field Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: MTRR: handle MSR_MTRRcap in kvm_mtrr_get_msrXiao Guangrong
MSR_MTRRcap is a MTRR msr so move the handler to the common place, also add some comments to make the hard code more readable Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-19KVM: x86: move MTRR related code to a separate fileXiao Guangrong
MTRR code locates in x86.c and mmu.c so that move them to a separate file to make the organization more clearer and it will be the place where we fully implement vMTRR Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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