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67730e6c53
Use the kernel's canonical $(ARCH) paths instead of the raw target triple for KVM selftests directories. KVM selftests are quite nearly the only place in the entire kernel that using the target triple for directories, tools/testing/selftests/drivers/s390x being the lone holdout. Using the kernel's preferred nomenclature eliminates the minor, but annoying, friction of having to translate to KVM's selftests directories, e.g. for pattern matching, opening files, running selftests, etc. Opportunsitically delete file comments that reference the full path of the file, as they are obviously prone to becoming stale, and serve no known purpose. Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Acked-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20241128005547.4077116-16-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 <sys/mman.h>
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#include <linux/fs.h>
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#include "test_util.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, uint8_t 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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