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Effectively revert the movement of code from kvm_util.h => kvm_util_base.h,
as the TL;DR of the justification for the move was to avoid #idefs and/or
circular dependencies between what ended up being ucall_common.h and what
was (and now again, is), kvm_util.h.
But avoiding #ifdef and circular includes is trivial: don't do that. The
cost of removing kvm_util_base.h is a few extra includes of ucall_common.h,
but that cost is practically nothing. On the other hand, having a "base"
version of a header that is really just the header itself is confusing,
and makes it weird/hard to choose names for headers that actually are
"base" headers, e.g. to hold core KVM selftests typedefs.
For all intents and purposes, this reverts commit
7d9a662ed9f0403e7b94940dceb81552b8edb931.
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20240314232637.2538648-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Allocate the common ucall pool using vm_vaddr_alloc_shared() so that the
ucall structures will be placed in shared (unencrypted) memory for VMs
with support for protected (encrypted) memory, e.g. x86's SEV.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerly Tng <ackerleytng@google.com>
cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
[sean: massage changelog]
Link: https://lore.kernel.org/r/20240223004258.3104051-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add printf-based GUEST_ASSERT macros and accompanying host-side support to
provide an assert-specific versions of GUEST_PRINTF(). To make it easier
to parse assert messages, for humans and bots alike, preserve/use the same
layout as host asserts, e.g. in the example below, the reported expression,
file, line number, and message are from the guest assertion, not the host
reporting of the assertion.
The call stack still captures the host reporting, but capturing the guest
stack is a less pressing concern, i.e. can be done in the future, and an
optimal solution would capture *both* the host and guest stacks, i.e.
capturing the host stack isn't an outright bug.
Running soft int test
==== Test Assertion Failure ====
x86_64/svm_nested_soft_inject_test.c:39: regs->rip != (unsigned long)l2_guest_code_int
pid=214104 tid=214104 errno=4 - Interrupted system call
1 0x0000000000401b35: run_test at svm_nested_soft_inject_test.c:191
2 0x00000000004017d2: main at svm_nested_soft_inject_test.c:212
3 0x0000000000415b03: __libc_start_call_main at libc-start.o:?
4 0x000000000041714f: __libc_start_main_impl at ??:?
5 0x0000000000401660: _start at ??:?
Expected IRQ at RIP 0x401e50, received IRQ at 0x401e50
Don't bother sharing code between ucall_assert() and ucall_fmt(), as
forwarding the variable arguments would either require using macros or
building a va_list, i.e. would make the code less readable and/or require
just as much copy+paste code anyways.
Gate the new macros with a flag so that tests can more or less be switched
over one-by-one. The slow conversion won't be perfect, e.g. library code
won't pick up the flag, but the only asserts in library code are of the
vanilla GUEST_ASSERT() variety, i.e. don't print out variables.
Add a temporary alias to GUEST_ASSERT_1() to fudge around ARM's
arch_timer.h header using GUEST_ASSERT_1(), thus thwarting any attempt to
convert tests one-by-one.
Link: https://lore.kernel.org/r/20230729003643.1053367-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add more flexibility to guest debugging and testing by adding
GUEST_PRINTF() and GUEST_ASSERT_FMT() to the ucall framework.
Add a sized buffer to the ucall structure to hold the formatted string,
i.e. to allow the guest to easily resolve the string, and thus avoid the
ugly pattern of the host side having to make assumptions about the desired
format, as well as having to pass around a large number of parameters.
The buffer size was chosen to accommodate most use cases, and based on
similar usage. E.g. printf() uses the same size buffer in
arch/x86/boot/printf.c. And 1KiB ought to be enough for anybody.
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
[sean: massage changelog, wrap macro param in ()]
Link: https://lore.kernel.org/r/20230729003643.1053367-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add additional pages to the guest to account for the number of pages
the ucall headers need. The only reason things worked before is the
ucall headers are fairly small. If they were ever to increase in
size the guest could run out of memory.
This is done in preparation for adding string formatting options to
the guest through the ucall framework which increases the size of
the ucall headers.
Fixes: 426729b2cf2e ("KVM: selftests: Add ucall pool based implementation")
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20230729003643.1053367-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use a magic value to signal a ucall_alloc() failure instead of simply
doing GUEST_ASSERT(). GUEST_ASSERT() relies on ucall_alloc() and so a
failure puts the guest into an infinite loop.
Use -1 as the magic value, as a real ucall struct should never wrap.
Reported-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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x86 Xen-for-KVM:
* Allow the Xen runstate information to cross a page boundary
* Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured
* add support for 32-bit guests in SCHEDOP_poll
x86 fixes:
* One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0).
* Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few
years back when eliminating unnecessary barriers when switching between
vmcs01 and vmcs02.
* Clean up the MSR filter docs.
* Clean up vmread_error_trampoline() to make it more obvious that params
must be passed on the stack, even for x86-64.
* Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective
of the current guest CPUID.
* Fudge around a race with TSC refinement that results in KVM incorrectly
thinking a guest needs TSC scaling when running on a CPU with a
constant TSC, but no hardware-enumerated TSC frequency.
* Advertise (on AMD) that the SMM_CTL MSR is not supported
* Remove unnecessary exports
Selftests:
* Fix an inverted check in the access tracking perf test, and restore
support for asserting that there aren't too many idle pages when
running on bare metal.
* Fix an ordering issue in the AMX test introduced by recent conversions
to use kvm_cpu_has(), and harden the code to guard against similar bugs
in the future. Anything that tiggers caching of KVM's supported CPUID,
kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if
the caching occurs before the test opts in via prctl().
* Fix build errors that occur in certain setups (unsure exactly what is
unique about the problematic setup) due to glibc overriding
static_assert() to a variant that requires a custom message.
* Introduce actual atomics for clear/set_bit() in selftests
Documentation:
* Remove deleted ioctls from documentation
* Various fixes
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MEM_REGION_TEST_DATA is meant to hold data explicitly used by a
selftest, not implicit allocations due to the selftests infrastructure.
Allocate the ucall pool from MEM_REGION_DATA much like the rest of the
selftests library allocations.
Fixes: 426729b2cf2e ("KVM: selftests: Add ucall pool based implementation")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Message-Id: <20221207214809.489070-5-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Drop the "atomic_" prefix from tools' atomic_test_and_set_bit() to
match the kernel nomenclature where test_and_set_bit() is atomic,
and __test_and_set_bit() provides the non-atomic variant.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221119013450.2643007-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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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
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Consolidate the actual copying of a ucall struct from guest=>host into
the common get_ucall(). Return a host virtual address instead of a guest
virtual address even though the addr_gva2hva() part could be moved to
get_ucall() too. Conceptually, get_ucall() is invoked from the host and
should return a host virtual address (and returning NULL for "nothing to
see here" is far superior to returning 0).
Use pointer shenanigans instead of an unnecessary bounce buffer when the
caller of get_ucall() provides a valid pointer.
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/20221006003409.649993-3-seanjc@google.com
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Make ucall() a common helper that populates struct ucall, and only calls
into arch code to make the actually call out to userspace.
Rename all arch-specific helpers to make it clear they're arch-specific,
and to avoid collisions with common helpers (one more on its way...)
Add WRITE_ONCE() to stores in ucall() code (as already done to aarch64
code in commit 9e2f6498efbb ("selftests: KVM: Handle compiler
optimizations in ucall")) to prevent clang optimizations breaking ucalls.
Cc: Colton Lewis <coltonlewis@google.com>
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/20221006003409.649993-2-seanjc@google.com
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