IF YOU WOULD LIKE TO GET AN ACCOUNT, please write an
email to Administrator. User accounts are meant only to access repo
and report issues and/or generate pull requests.
This is a purpose-specific Git hosting for
BaseALT
projects. Thank you for your understanding!
Только зарегистрированные пользователи имеют доступ к сервису!
Для получения аккаунта, обратитесь к администратору.
All Hyper-V specific tests issuing hypercalls need this.
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-33-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
HYPERV_LINUX_OS_ID needs to be written to HV_X64_MSR_GUEST_OS_ID by
each Hyper-V specific selftest.
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-32-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
set_xmm()/get_xmm() helpers are fairly useless as they only read 64 bits
from 128-bit registers. Moreover, these helpers are not used. Borrow
_kvm_read_sse_reg()/_kvm_write_sse_reg() from KVM limiting them to
XMM0-XMM8 for now.
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-31-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that KVM isn't littered with "struct hv_enlightenments" casts, rename
the struct to "hv_vmcb_enlightenments" to highlight the fact that the
struct is specifically for SVM's VMCB.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-5-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a union to provide hv_enlightenments side-by-side with the sw_reserved
bytes that Hyper-V's enlightenments overlay. Casting sw_reserved
everywhere is messy, confusing, and unnecessarily unsafe.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move Hyper-V's VMCB "struct hv_enlightenments" to the svm.h header so
that the struct can be referenced in "struct vmcb_control_area".
Alternatively, a dedicated header for SVM+Hyper-V could be added, a la
x86_64/evmcs.h, but it doesn't appear that Hyper-V will end up needing
a wholesale replacement for the VMCB.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move Hyper-V's VMCB enlightenment definitions to the TLFS header; the
definitions come directly from the TLFS[*], not from KVM.
No functional change intended.
[*] https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/datatypes/hv_svm_enlightened_vmcb_fields
[vitaly: rename VMCB_HV_ -> HV_VMCB_ to match the rest of
hyperv-tlfs.h, keep svm/hyperv.h]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This fixes three issues in nested SVM:
1) in the shutdown_interception() vmexit handler we call kvm_vcpu_reset().
However, if running nested and L1 doesn't intercept shutdown, the function
resets vcpu->arch.hflags without properly leaving the nested state.
This leaves the vCPU in inconsistent state and later triggers a kernel
panic in SVM code. The same bug can likely be triggered by sending INIT
via local apic to a vCPU which runs a nested guest.
On VMX we are lucky that the issue can't happen because VMX always
intercepts triple faults, thus triple fault in L2 will always be
redirected to L1. Plus, handle_triple_fault() doesn't reset the vCPU.
INIT IPI can't happen on VMX either because INIT events are masked while
in VMX mode.
Secondarily, KVM doesn't honour SHUTDOWN intercept bit of L1 on SVM.
A normal hypervisor should always intercept SHUTDOWN, a unit test on
the other hand might want to not do so.
Finally, the guest can trigger a kernel non rate limited printk on SVM
from the guest, which is fixed as well.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a SVM implementation to triple_fault_test to test that
emulated/injected shutdown works.
Since instead of the VMX, the SVM allows the hypervisor to avoid
intercepting shutdown in guest, don't intercept shutdown to test that
KVM suports this correctly.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-9-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add test that tests that on SVM if L1 doesn't intercept SHUTDOWN,
then L2 crashes L1 and doesn't crash L2
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-7-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
struct idt_entry will be used for a test which will break IDT on purpose.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-6-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that a VM isn't needed to check for nEPT support, assert that KVM
supports nEPT in prepare_eptp() instead of skipping the test, and push
the TEST_REQUIRE() check out to individual tests. The require+assert are
somewhat redundant and will incur some amount of ongoing maintenance
burden, but placing the "require" logic in the test makes it easier to
find/understand a test's requirements and in this case, provides a very
strong hint that the test cares about nEPT.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20220927165209.930904-1-dmatlack@google.com
[sean: rebase on merged code, write changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
When checking for nEPT support in KVM, use kvm_get_feature_msr() instead
of vcpu_get_msr() to retrieve KVM's default TRUE_PROCBASED_CTLS and
PROCBASED_CTLS2 MSR values, i.e. don't require a VM+vCPU to query nEPT
support.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20220927165209.930904-1-dmatlack@google.com
[sean: rebase on merged code, write changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Drop kvm_get_supported_cpuid_entry() and its inner helper now that all
known usage can use X86_FEATURE_*, X86_PROPERTY_*, X86_PMU_FEATURE_*, or
the dedicated Family/Model helpers. Providing "raw" access to CPUID
leafs is undesirable as it encourages open coding CPUID checks, which is
often error prone and not self-documenting.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-13-seanjc@google.com
Add KVM variants of the x86 Family and Model helpers, and use them in the
PMU event filter test. Open code the retrieval of KVM's supported CPUID
entry 0x1.0 in anticipation of dropping kvm_get_supported_cpuid_entry().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-12-seanjc@google.com
Add dedicated helpers for getting x86's Family and Model, which are the
last holdouts that "need" raw access to CPUID information. FMS info is
a mess and requires not only splicing together multiple values, but
requires doing so conditional in the Family case.
Provide wrappers to reduce the odds of copy+paste errors, but mostly to
allow for the eventual removal of kvm_get_supported_cpuid_entry().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-11-seanjc@google.com
Add an X86_PMU_FEATURE_* framework to simplify probing architectural
events on Intel PMUs, which require checking the length of a bit vector
and the _absence_ of a "feature" bit. Add helpers for both KVM and
"this CPU", and use the newfangled magic (along with X86_PROPERTY_*)
to clean up pmu_event_filter_test.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-10-seanjc@google.com
Add X86_PROPERTY_PMU_VERSION and use it in vmx_pmu_caps_test to replace
open coded versions of the same functionality.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-9-seanjc@google.com
Add and use x86 "properties" for the myriad AMX CPUID values that are
validated by the AMX test. Drop most of the test's single-usage
helpers so that the asserts more precisely capture what check failed.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-8-seanjc@google.com
Extent X86_PROPERTY_* support to KVM, i.e. add kvm_cpu_property() and
kvm_cpu_has_p(), and use the new helpers in kvm_get_cpu_address_width().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-7-seanjc@google.com
Use X86_PROPERTY_MAX_KVM_LEAF to replace the equivalent open coded check
on KVM's maximum paravirt CPUID leaf.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-5-seanjc@google.com
Introduce X86_PROPERTY_* to allow retrieving values/properties from CPUID
leafs, e.g. MAXPHYADDR from CPUID.0x80000008. Use the same core code as
X86_FEATURE_*, the primary difference is that properties are multi-bit
values, whereas features enumerate a single bit.
Add this_cpu_has_p() to allow querying whether or not a property exists
based on the maximum leaf associated with the property, e.g. MAXPHYADDR
doesn't exist if the max leaf for 0x8000_xxxx is less than 0x8000_0008.
Use the new property infrastructure in vm_compute_max_gfn() to prove
that the code works as intended. Future patches will convert additional
selftests code.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-4-seanjc@google.com
Refactor the X86_FEATURE_* framework to prepare for extending the core
logic to support "properties". The "feature" framework allows querying a
single CPUID bit to detect the presence of a feature; the "property"
framework will extend the idea to allow querying a value, i.e. to get a
value that is a set of contiguous bits in a CPUID leaf.
Opportunistically add static asserts to ensure features are fully defined
at compile time, and to try and catch mistakes in the definition of
features.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-3-seanjc@google.com
Add X86_FEATURE_PAE and use it to guesstimate the MAXPHYADDR when the
MAXPHYADDR CPUID entry isn't supported.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-2-seanjc@google.com
Add a selftest to exercise the KVM_CAP_EXIT_ON_EMULATION_FAILURE
capability.
This capability is also exercised through
smaller_maxphyaddr_emulation_test, but that test requires
allow_smaller_maxphyaddr=Y, which is off by default on Intel when ept=Y
and unconditionally disabled on AMD when npt=Y. This new test ensures
that KVM_CAP_EXIT_ON_EMULATION_FAILURE is exercised independent of
allow_smaller_maxphyaddr.
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-11-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Change smaller_maxphyaddr_emulation_test to expect a #PF(RSVD), rather
than an emulation failure, when TDP is disabled. KVM only needs to
emulate instructions to emulate a smaller guest.MAXPHYADDR when TDP is
enabled.
Fixes: 39bbcc3a4e39 ("selftests: kvm: Allows userspace to handle emulation errors.")
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-10-dmatlack@google.com
[sean: massage comment to talk about having to emulate due to MAXPHYADDR]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Provide the error code on a fault in KVM_ASM_SAFE(), e.g. to allow tests
to assert that #PF generates the correct error code without needing to
manually install a #PF handler. Use r10 as the scratch register for the
error code, as it's already clobbered by the asm blob (loaded with the
RIP of the to-be-executed instruction). Deliberately load the output
"error_code" even in the non-faulting path so that error_code is always
initialized with deterministic data (the aforementioned RIP), i.e to
ensure a selftest won't end up with uninitialized consumption regardless
of how KVM_ASM_SAFE() is used.
Don't clear r10 in the non-faulting case and instead load error code with
the RIP (see above). The error code is valid if and only if an exception
occurs, and '0' isn't necessarily a better "invalid" value, e.g. '0'
could result in false passes for a buggy test.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-9-dmatlack@google.com
Clear R9 in the non-faulting path of KVM_ASM_SAFE() and fall through to
to a common load of "vector" to effectively load "vector" with '0' to
reduce the code footprint of the asm blob, to reduce the runtime overhead
of the non-faulting path (when "vector" is stored in a register), and so
that additional output constraints that are valid if and only if a fault
occur are loaded even in the non-faulting case.
A future patch will add a 64-bit output for the error code, and if its
output is not explicitly loaded with _something_, the user of the asm
blob can end up technically consuming uninitialized data. Using a
common path to load the output constraints will allow using an existing
scratch register, e.g. r10, to hold the error code in the faulting path,
while also guaranteeing the error code is initialized with deterministic
data in the non-faulting patch (r10 is loaded with the RIP of
to-be-executed instruction).
Consuming the error code when a fault doesn't occur would obviously be a
test bug, but there's no guarantee the compiler will detect uninitialized
consumption. And conversely, it's theoretically possible that the
compiler might throw a false positive on uninitialized data, e.g. if the
compiler can't determine that the non-faulting path won't touch the error
code.
Alternatively, the error code could be explicitly loaded in the
non-faulting path, but loading a 64-bit memory|register output operand
with an explicitl value requires a sign-extended "MOV imm32, r/m64",
which isn't exactly straightforward and has a largish code footprint.
And loading the error code with what is effectively garbage (from a
scratch register) avoids having to choose an arbitrary value for the
non-faulting case.
Opportunistically remove a rogue asterisk in the block comment.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-8-dmatlack@google.com
Copy KVM's macros for page fault error masks into processor.h so they
can be used in selftests.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-7-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Move the flds instruction emulation failure handling code to a header
so it can be re-used in an upcoming test.
No functional change intended.
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-5-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Delete a bunch of code related to ucall handling from
smaller_maxphyaddr_emulation_test. The only thing
smaller_maxphyaddr_emulation_test needs to check is that the vCPU exits
with UCALL_DONE after the second vcpu_run().
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-4-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Hard-code the flds instruction and assert the exact instruction bytes
are present in run->emulation_failure. The test already requires the
instruction bytes to be present because that's the only way the test
will advance the RIP past the flds and get to GUEST_DONE().
Note that KVM does not necessarily return exactly 2 bytes in
run->emulation_failure since it may not know the exact instruction
length in all cases. So just assert that
run->emulation_failure.insn_size is at least 2.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-3-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Rename emulator_error_test to smaller_maxphyaddr_emulation_test and
update the comment at the top of the file to document that this is
explicitly a test to validate that KVM emulates instructions in response
to an EPT violation when emulating a smaller MAXPHYADDR.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-2-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
In xapic_state_test's test_icr(), explicitly skip iterations that would
match vcpu->id instead of assuming vcpu->id is '0', so that IPIs are
are correctly sent to non-existent vCPUs.
Suggested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/kvm/YyoZr9rXSSMEtdh5@google.com
Signed-off-by: Gautam Menghani <gautammenghani201@gmail.com>
Link: https://lore.kernel.org/r/20221017175819.12672-1-gautammenghani201@gmail.com
[sean: massage shortlog and changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add arch specific API kvm_arch_vm_post_create to perform any required setup
after VM creation.
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Link: https://lore.kernel.org/r/20221115213845.3348210-4-vannapurve@google.com
[sean: place x86's implementation by vm_arch_vcpu_add()]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Introduce arch specific API: kvm_selftest_arch_init to allow each arch to
handle initialization before running any selftest logic.
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Link: https://lore.kernel.org/r/20221115213845.3348210-3-vannapurve@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Consolidate common startup logic in one place by implementing a single
setup function with __attribute((constructor)) for all selftests within
kvm_util.c.
This allows moving logic like:
/* Tell stdout not to buffer its content */
setbuf(stdout, NULL);
to a single file for all selftests.
This will also allow any required setup at entry in future to be done in
common main function.
Link: https://lore.kernel.org/lkml/Ywa9T+jKUpaHLu%2Fl@google.com
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Link: https://lore.kernel.org/r/20221115213845.3348210-2-vannapurve@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Play nice with huge pages when getting PTEs and translating GVAs to GPAs,
there's no reason to disallow using huge pages in selftests. Use
PG_LEVEL_NONE to indicate that the caller doesn't care about the mapping
level and just wants to get the pte+level.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-8-seanjc@google.com
Verify the parent PTE is PRESENT when getting a child via virt_get_pte()
so that the helper can be used for getting PTEs/GPAs without losing
sanity checks that the walker isn't wandering into the weeds.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-5-seanjc@google.com
Remove the pointless shift from GPA=>GFN and immediately back to
GFN=>GPA when creating guest page tables. Ignore the other walkers
that have a similar pattern for the moment, they will be converted
to use virt_get_pte() in the near future.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-4-seanjc@google.com
Drop the reserved bit checks from the helper to retrieve a PTE, there's
very little value in sanity checking the constructed page tables as any
will quickly be noticed in the form of an unexpected #PF. The checks
also place unnecessary restrictions on the usage of the helpers, e.g. if
a test _wanted_ to set reserved bits for whatever reason.
Removing the NX check in particular allows for the removal of the @vcpu
param, which will in turn allow the helper to be reused nearly verbatim
for addr_gva2gpa().
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-3-seanjc@google.com
Drop vm_{g,s}et_page_table_entry() and instead expose the "inner"
helper (was _vm_get_page_table_entry()) that returns a _pointer_ to the
PTE, i.e. let tests directly modify PTEs instead of bouncing through
helpers that just make life difficult.
Opportunsitically use BIT_ULL() in emulator_error_test, and use the
MAXPHYADDR define to set the "rogue" GPA bit instead of open coding the
same value.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-2-seanjc@google.com
There is a spelling mistake in an assert message. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20220928213458.64089-1-colin.i.king@gmail.com
[sean: fix an ironic typo in the changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
To play nice with guests whose stack memory is encrypted, e.g. AMD SEV,
introduce a new "ucall pool" implementation that passes the ucall struct
via dedicated memory (which can be mapped shared, a.k.a. as plain text).
Because not all architectures have access to the vCPU index in the guest,
use a bitmap with atomic accesses to track which entries in the pool are
free/used. A list+lock could also work in theory, but synchronizing the
individual pointers to the guest would be a mess.
Note, there's no need to rewalk the bitmap to ensure success. If all
vCPUs are simply allocating, success is guaranteed because there are
enough entries for all vCPUs. If one or more vCPUs are freeing and then
reallocating, success is guaranteed because vCPUs _always_ walk the
bitmap from 0=>N; if vCPU frees an entry and then wins a race to
re-allocate, then either it will consume the entry it just freed (bit is
the first free bit), or the losing vCPU is guaranteed to see the freed
bit (winner consumes an earlier bit, which the loser hasn't yet visited).
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Signed-off-by: Peter Gonda <pgonda@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-8-seanjc@google.com
Drop ucall_uninit() and ucall_arch_uninit() now that ARM doesn't modify
the host's copy of ucall_exit_mmio_addr, i.e. now that there's no need to
reset the pointer before potentially creating a new VM. The few calls to
ucall_uninit() are all immediately followed by kvm_vm_free(), and that is
likely always going to hold true, i.e. it's extremely unlikely a test
will want to effectively disable ucall in the middle of a test.
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-7-seanjc@google.com
Fix a mostly-theoretical bug where ARM's ucall MMIO setup could result in
different VMs stomping on each other by cloberring the global pointer.
Fix the most obvious issue by saving the MMIO gpa into the VM.
A more subtle bug is that creating VMs in parallel (on multiple tasks)
could result in a VM using the wrong address. Synchronizing a global to
a guest effectively snapshots the value on a per-VM basis, i.e. the
"global" is already prepped to work with multiple VMs, but setting the
global in the host is not thread-safe. To fix that bug, add
write_guest_global() to allow stuffing a VM's copy of a "global" without
modifying the host value.
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-6-seanjc@google.com
Do init_ucall() automatically during VM creation to kill two (three?)
birds with one stone.
First, initializing ucall immediately after VM creations allows forcing
aarch64's MMIO ucall address to immediately follow memslot0. This is
still somewhat fragile as tests could clobber the MMIO address with a
new memslot, but it's safe-ish since tests have to be conversative when
accounting for memslot0. And this can be hardened in the future by
creating a read-only memslot for the MMIO page (KVM ARM exits with MMIO
if the guest writes to a read-only memslot). Add a TODO to document that
selftests can and should use a memslot for the ucall MMIO (doing so
requires yet more rework because tests assumes thay can use all memslots
except memslot0).
Second, initializing ucall for all VMs prepares for making ucall
initialization meaningful on all architectures. aarch64 is currently the
only arch that needs to do any setup, but that will change in the future
by switching to a pool-based implementation (instead of the current
stack-based approach).
Lastly, defining the ucall MMIO address from common code will simplify
switching all architectures (except s390) to a common MMIO-based ucall
implementation (if there's ever sufficient motivation to do so).
Cc: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-4-seanjc@google.com
