From: Robert Hoo <robert.hu@xxxxxxxxxxxxxxx> This unit test covers: 1. CR4.LAM_SUP toggles. 2. Memory & MMIO access with supervisor mode address with LAM metadata. 3. INVLPG memory operand doesn't contain LAM meta data, if the address is non-canonical form then the INVLPG is the same as a NOP (no #GP). 4. INVPCID memory operand (descriptor pointer) could contain LAM meta data, however, the address in the descriptor should be canonical. In x86/unittests.cfg, add 2 test cases/guest conf, with and without LAM. LAM feature spec: https://cdrdv2.intel.com/v1/dl/getContent/671368, Chapter LINEAR ADDRESS MASKING (LAM) Signed-off-by: Robert Hoo <robert.hu@xxxxxxxxxxxxxxx> Co-developed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> Reviewed-by: Chao Gao <chao.gao@xxxxxxxxx> --- v7： - Rename is_la57()/lam_sup_active() to is_la57_enabled()/is_lam_sup_enabled(), and move them to processor.h (Sean) - Drop cr4_set_lam_sup()/cr4_clear_lam_sup() and use write_cr4_safe() instead. (Sean) - Add get_lam_mask() to get lam status based on the address and vCPU state. (Sean) - Drop the wrappers for INVLPG since INVLPG never faults. (Sean) - Drop the wrapper for INVPCID and use invpcid_safe() instead. (Sean) - Drop the check for X86_FEATURE_PCID. (Sean) --- lib/x86/processor.h | 20 +++++ x86/Makefile.x86_64 | 1 + x86/lam.c | 214 ++++++++++++++++++++++++++++++++++++++++++++ x86/unittests.cfg | 10 +++ 4 files changed, 245 insertions(+) create mode 100644 x86/lam.c diff --git a/lib/x86/processor.h b/lib/x86/processor.h index f7f2df50..a38f87ed 100644 --- a/lib/x86/processor.h +++ b/lib/x86/processor.h @@ -8,6 +8,14 @@ #include <stdint.h> #define NONCANONICAL 0xaaaaaaaaaaaaaaaaull +#define LAM57_MASK GENMASK_ULL(62, 57) +#define LAM48_MASK GENMASK_ULL(62, 48) + +/* Set metadata with non-canonical pattern in mask bits of a linear address */ +static inline u64 set_la_non_canonical(u64 src, u64 mask) +{ + return (src & ~mask) | (NONCANONICAL & mask); +} #ifdef __x86_64__ # define R "r" @@ -120,6 +128,8 @@ #define X86_CR4_CET BIT(X86_CR4_CET_BIT) #define X86_CR4_PKS_BIT (24) #define X86_CR4_PKS BIT(X86_CR4_PKS_BIT) +#define X86_CR4_LAM_SUP_BIT (28) +#define X86_CR4_LAM_SUP BIT(X86_CR4_LAM_SUP_BIT) #define X86_EFLAGS_CF_BIT (0) #define X86_EFLAGS_CF BIT(X86_EFLAGS_CF_BIT) @@ -968,4 +978,14 @@ struct invpcid_desc { u64 addr : 64; } __attribute__((packed)); +static inline bool is_la57_enabled(void) +{ + return !!(read_cr4() & X86_CR4_LA57); +} + +static inline bool is_lam_sup_enabled(void) +{ + return !!(read_cr4() & X86_CR4_LAM_SUP); +} + #endif diff --git a/x86/Makefile.x86_64 b/x86/Makefile.x86_64 index 2771a6fa..e5db2365 100644 --- a/x86/Makefile.x86_64 +++ b/x86/Makefile.x86_64 @@ -38,6 +38,7 @@ tests += $(TEST_DIR)/rdpru.$(exe) tests += $(TEST_DIR)/pks.$(exe) tests += $(TEST_DIR)/pmu_lbr.$(exe) tests += $(TEST_DIR)/pmu_pebs.$(exe) +tests += $(TEST_DIR)/lam.$(exe) ifeq ($(CONFIG_EFI),y) tests += $(TEST_DIR)/amd_sev.$(exe) diff --git a/x86/lam.c b/x86/lam.c new file mode 100644 index 00000000..2f95b6c9 --- /dev/null +++ b/x86/lam.c @@ -0,0 +1,214 @@ +/* + * Intel LAM unit test + * + * Copyright (C) 2023 Intel + * + * Author: Robert Hoo <robert.hu@xxxxxxxxxxxxxxx> + * Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> + * + * This work is licensed under the terms of the GNU LGPL, version 2 or + * later. + */ + +#include "libcflat.h" +#include "processor.h" +#include "desc.h" +#include "vmalloc.h" +#include "alloc_page.h" +#include "vm.h" +#include "asm/io.h" +#include "ioram.h" + +static void test_cr4_lam_set_clear(void) +{ + int vector; + bool has_lam = this_cpu_has(X86_FEATURE_LAM); + + vector = write_cr4_safe(read_cr4() | X86_CR4_LAM_SUP); + report(has_lam ? !vector : vector == GP_VECTOR, + "Expected CR4.LAM_SUP=1 to %s", has_lam ? "succeed" : "#GP"); + + vector = write_cr4_safe(read_cr4() & ~X86_CR4_LAM_SUP); + report(!vector, "Expected CR4.LAM_SUP=0 to succeed"); +} + +/* Refer to emulator.c */ +static void do_mov(void *mem) +{ + unsigned long t1, t2; + + t1 = 0x123456789abcdefull & -1ul; + asm volatile("mov %[t1], (%[mem])\n\t" + "mov (%[mem]), %[t2]" + : [t2]"=r"(t2) + : [t1]"r"(t1), [mem]"r"(mem) + : "memory"); + report(t1 == t2, "Mov result check"); +} + +static bool get_lam_mask(u64 address, u64* lam_mask) +{ + /* + * Use LAM57_MASK as mask to construct non-canonical address if LAM is + * not supported or enabled. + */ + *lam_mask = LAM57_MASK; + + /* + * Bit 63 determines if the address should be treated as a user address + * or a supervisor address. + */ + if (address & BIT_ULL(63)) { + if (!(is_lam_sup_enabled())) + return false; + + if (!is_la57_enabled()) + *lam_mask = LAM48_MASK; + return true; + } + + /* TODO: Get LAM mask for userspace address. */ + return false; +} + + +static void test_ptr(u64* ptr, bool is_mmio) +{ + u64 lam_mask; + bool lam_active, fault; + + lam_active = get_lam_mask((u64)ptr, &lam_mask); + + fault = test_for_exception(GP_VECTOR, do_mov, ptr); + report(!fault, "Expected access to untagged address for %s to succeed", + is_mmio ? "MMIO" : "memory"); + + ptr = (u64 *)set_la_non_canonical((u64)ptr, lam_mask); + fault = test_for_exception(GP_VECTOR, do_mov, ptr); + report(fault != lam_active, "Expected access to tagged address for %s %s LAM to %s", + is_mmio ? "MMIO" : "memory", lam_active ? "with" : "without", + lam_active ? "succeed" : "#GP"); +} + +/* invlpg with tagged address is same as NOP, no #GP expected. */ +static void test_invlpg(void *va, bool fep) +{ + u64 lam_mask; + u64 *ptr; + + /* + * The return value is not checked, invlpg should never faults no matter + * LAM is supported or not. + */ + get_lam_mask((u64)va, &lam_mask); + ptr = (u64 *)set_la_non_canonical((u64)va, lam_mask); + if (fep) + asm volatile(KVM_FEP "invlpg (%0)" ::"r" (ptr) : "memory"); + else + invlpg(ptr); + + report(true, "Expected %sINVLPG with tagged addr to succeed", fep ? "fep: " : ""); +} + +/* LAM doesn't apply to the linear address in the descriptor of invpcid */ +static void test_invpcid(void *data) +{ + /* + * Reuse the memory address for the descriptor since stack memory + * address in KUT doesn't follow the kernel address space partitions. + */ + struct invpcid_desc *desc_ptr = (struct invpcid_desc *)data; + int vector; + u64 lam_mask; + bool lam_active; + + if (!this_cpu_has(X86_FEATURE_INVPCID)) { + report_skip("INVPCID not supported"); + return; + } + + lam_active = get_lam_mask((u64)data, &lam_mask); + + memset(desc_ptr, 0, sizeof(struct invpcid_desc)); + desc_ptr->addr = (u64)data; + + vector = invpcid_safe(0, desc_ptr); + report(!vector, + "Expected INVPCID with untagged pointer + untagged addr to succeed"); + + desc_ptr->addr = set_la_non_canonical(desc_ptr->addr, lam_mask); + vector = invpcid_safe(0, desc_ptr); + report(vector==GP_VECTOR, + "Expected INVPCID with untagged pointer + tagged addr to #GP"); + + desc_ptr = (struct invpcid_desc *)set_la_non_canonical((u64)desc_ptr, + lam_mask); + vector = invpcid_safe(0, desc_ptr); + report(vector==GP_VECTOR, + "Expected INVPCID with tagged pointer + tagged addr to #GP"); + + desc_ptr = (struct invpcid_desc *)data; + desc_ptr->addr = (u64)data; + desc_ptr = (struct invpcid_desc *)set_la_non_canonical((u64)desc_ptr, + lam_mask); + vector = invpcid_safe(0, desc_ptr); + report(lam_active ? !vector : vector==GP_VECTOR, + "Expected INVPCID with tagged pointer + untagged addr to %s", + lam_active? "succeed" : "#GP"); +} + +static void test_lam_sup(void) +{ + void *vaddr, *vaddr_mmio; + phys_addr_t paddr; + unsigned long cr4 = read_cr4(); + int vector; + + /* + * KUT initializes vfree_top to 0 for X86_64, and each virtual address + * allocation decreases the size from vfree_top. It's guaranteed that + * the return value of alloc_vpage() is considered as kernel mode + * address and canonical since only a small mount virtual address range + * is allocated in this test. + */ + vaddr = alloc_vpage(); + vaddr_mmio = alloc_vpage(); + paddr = virt_to_phys(alloc_page()); + install_page(current_page_table(), paddr, vaddr); + install_page(current_page_table(), IORAM_BASE_PHYS, vaddr_mmio); + + test_cr4_lam_set_clear(); + + /* Set for the following LAM_SUP tests. */ + if (this_cpu_has(X86_FEATURE_LAM)) { + vector = write_cr4_safe(cr4 | X86_CR4_LAM_SUP); + report(!vector && is_lam_sup_enabled(), + "Expected CR4.LAM_SUP=1 to succeed"); + } + + /* Test for normal memory. */ + test_ptr(vaddr, false); + /* Test for MMIO to trigger instruction emulation. */ + test_ptr(vaddr_mmio, true); + test_invpcid(vaddr); + test_invlpg(vaddr, false); + if (is_fep_available()) + test_invlpg(vaddr, true); + else + report_skip("Skipping tests the forced emulation, " + "use kvm.force_emulation_prefix=1 to enable\n"); +} + +int main(int ac, char **av) +{ + setup_vm(); + + if (!this_cpu_has(X86_FEATURE_LAM)) + report_info("This CPU doesn't support LAM feature\n"); + else + report_info("This CPU supports LAM feature\n"); + + test_lam_sup(); + + return report_summary(); +} diff --git a/x86/unittests.cfg b/x86/unittests.cfg index 7c1691a9..f1178edd 100644 --- a/x86/unittests.cfg +++ b/x86/unittests.cfg @@ -490,3 +490,13 @@ file = cet.flat arch = x86_64 smp = 2 extra_params = -enable-kvm -m 2048 -cpu host + +[intel-lam] +file = lam.flat +arch = x86_64 +extra_params = -enable-kvm -cpu host + +[intel-no-lam] +file = lam.flat +arch = x86_64 +extra_params = -enable-kvm -cpu host,-lam -- 2.43.2
