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6d3790bc68
Include both linux/mman.h (the kernel provided version) and sys/mman.h (the
libc provided version) throughout KVM selftests, by way of kvm_syscalls.h
(which should have been including sys/mman.h anyways). Pulling in the
kernel's version fixes compilation errors with the guest_memfd test on
older versions of libc due to a recent commit adding MADV_COLLAPSE testing.
In file included from include/kvm_util.h:8,
from guest_memfd_test.c:21:
guest_memfd_test.c: In function ‘test_collapse’:
guest_memfd_test.c:219:47: error: ‘MADV_COLLAPSE’ undeclared (first use in this function); did you mean ‘MADV_COLD’?
219 | TEST_ASSERT_EQ(madvise(mem, pmd_size, MADV_COLLAPSE), -1);
| ^~~~~~~~~~~~~
include/test_util.h:62:16: note: in definition of macro ‘TEST_ASSERT_EQ’
62 | typeof(a) __a = (a); \
| ^
guest_memfd_test.c:219:47: note: each undeclared identifier is reported only once for each function it appears in
219 | TEST_ASSERT_EQ(madvise(mem, pmd_size, MADV_COLLAPSE), -1);
| ^~~~~~~~~~~~~
include/test_util.h:62:16: note: in definition of macro ‘TEST_ASSERT_EQ’
62 | typeof(a) __a = (a); \
| ^
Route the includes through kvm_syscalls.h to try and avoid a future game
of whack-a-mole, i.e. so that future expansion of test coverage doesn't run
into the same problem.
To discourage use of sys/mman.h, opportunistically include the kernel's
version of mman.h in test_util.h as it only needs MAP_SHARED, i.e. only
needs the full set of kernel defs, not the libc syscall wrappers.
Fixes: 9830209b4a ("KVM: selftests: Test MADV_COLLAPSE on guest_memfd")
Reported-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Closes: https://lore.kernel.org/all/20260427204313.50741-1-rick.p.edgecombe@intel.com
Link: https://patch.msgid.link/20260428012503.1213654-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Test shared zeropage handling (with/without storage keys)
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*
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* Copyright (C) 2024, Red Hat, Inc.
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*/
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#include <linux/fs.h>
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#include "test_util.h"
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#include "kvm_syscalls.h"
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#include "kvm_util.h"
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#include "kselftest.h"
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#include "ucall_common.h"
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static void set_storage_key(void *addr, u8 skey)
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{
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asm volatile("sske %0,%1" : : "d" (skey), "a" (addr));
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}
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static void guest_code(void)
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{
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/* Issue some storage key instruction. */
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set_storage_key((void *)0, 0x98);
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GUEST_DONE();
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}
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/*
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* Returns 1 if the shared zeropage is mapped, 0 if something else is mapped.
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* Returns < 0 on error or if nothing is mapped.
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*/
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static int maps_shared_zeropage(int pagemap_fd, void *addr)
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{
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struct page_region region;
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struct pm_scan_arg arg = {
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.start = (uintptr_t)addr,
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.end = (uintptr_t)addr + 4096,
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.vec = (uintptr_t)®ion,
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.vec_len = 1,
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.size = sizeof(struct pm_scan_arg),
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.category_mask = PAGE_IS_PFNZERO,
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.category_anyof_mask = PAGE_IS_PRESENT,
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.return_mask = PAGE_IS_PFNZERO,
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};
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return ioctl(pagemap_fd, PAGEMAP_SCAN, &arg);
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}
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int main(int argc, char *argv[])
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{
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char *mem, *page0, *page1, *page2, tmp;
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const size_t pagesize = getpagesize();
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struct kvm_vcpu *vcpu;
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struct kvm_vm *vm;
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struct ucall uc;
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int pagemap_fd;
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ksft_print_header();
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ksft_set_plan(3);
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/*
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* We'll use memory that is not mapped into the VM for simplicity.
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* Shared zeropages are enabled/disabled per-process.
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*/
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mem = mmap(0, 3 * pagesize, PROT_READ, MAP_PRIVATE | MAP_ANON, -1, 0);
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TEST_ASSERT(mem != MAP_FAILED, "mmap() failed");
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/* Disable THP. Ignore errors on older kernels. */
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madvise(mem, 3 * pagesize, MADV_NOHUGEPAGE);
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page0 = mem;
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page1 = page0 + pagesize;
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page2 = page1 + pagesize;
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/* Can we even detect shared zeropages? */
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pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
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TEST_REQUIRE(pagemap_fd >= 0);
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tmp = *page0;
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asm volatile("" : "+r" (tmp));
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TEST_REQUIRE(maps_shared_zeropage(pagemap_fd, page0) == 1);
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vm = vm_create_with_one_vcpu(&vcpu, guest_code);
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/* Verify that we get the shared zeropage after VM creation. */
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tmp = *page1;
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asm volatile("" : "+r" (tmp));
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ksft_test_result(maps_shared_zeropage(pagemap_fd, page1) == 1,
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"Shared zeropages should be enabled\n");
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/*
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* Let our VM execute a storage key instruction that should
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* unshare all shared zeropages.
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*/
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vcpu_run(vcpu);
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get_ucall(vcpu, &uc);
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TEST_ASSERT_EQ(uc.cmd, UCALL_DONE);
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/* Verify that we don't have a shared zeropage anymore. */
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ksft_test_result(!maps_shared_zeropage(pagemap_fd, page1),
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"Shared zeropage should be gone\n");
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/* Verify that we don't get any new shared zeropages. */
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tmp = *page2;
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asm volatile("" : "+r" (tmp));
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ksft_test_result(!maps_shared_zeropage(pagemap_fd, page2),
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"Shared zeropages should be disabled\n");
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kvm_vm_free(vm);
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ksft_finished();
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}
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