On Sun, Mar 19, 2023 at 04:22:23PM +0800, Binbin Wu wrote:
+#define LAM57_BITS 6
+#define LAM48_BITS 15
+#define LAM57_MASK GENMASK_ULL(62, 57)
+#define LAM48_MASK GENMASK_ULL(62, 48)
+
+struct invpcid_desc {
+ u64 pcid : 12;
+ u64 rsv : 52;
+ u64 addr : 64;
u64 addr;
+
+};
+static int get_sup_lam_bits(void)
+{
+ if (this_cpu_has(X86_FEATURE_LA57) && read_cr4() & X86_CR4_LA57)
+ return LAM57_BITS;
+ else
+ return LAM48_BITS;
+}
+
+/* According to LAM mode, set metadata in high bits */
+static u64 set_metadata(u64 src, unsigned long lam)
+{
+ u64 metadata;
+
+ switch (lam) {
+ case LAM57_BITS: /* Set metadata in bits 62:57 */
+ metadata = (NONCANONICAL & ((1UL << LAM57_BITS) - 1)) << 57;
+ metadata |= (src & ~(LAM57_MASK));
this can be simplified to
return (src & ~LAM47_MASK) | (NONCANONICAL & LAM47_MASK);
and you can pass a mask to set_metadata() and set mask to 0 if LAM isn't
enabled. Then set_metadata() can be further simplified to
return (src & ~mask) | (NONCANONICAL & mask);
+ break;
+ case LAM48_BITS: /* Set metadata in bits 62:48 */
+ metadata = (NONCANONICAL & ((1UL << LAM48_BITS) - 1)) << 48;
+ metadata |= (src & ~(LAM48_MASK));
+ break;
+ default:
+ metadata = src;
+ break;
+ }
+
+ return metadata;
+}
+
+static void cr4_set_lam_sup(void *data)
+{
+ unsigned long cr4;
+
+ cr4 = read_cr4();
+ write_cr4_safe(cr4 | X86_CR4_LAM_SUP);
+}
+
+static void cr4_clear_lam_sup(void *data)
+{
+ unsigned long cr4;
+
+ cr4 = read_cr4();
+ write_cr4_safe(cr4 & ~X86_CR4_LAM_SUP);
+}
+
+static void test_cr4_lam_set_clear(bool lam_enumerated)
+{
+ bool fault;
+
+ fault = test_for_exception(GP_VECTOR, &cr4_set_lam_sup, NULL);
+ if (lam_enumerated)
+ report(!fault && (read_cr4() & X86_CR4_LAM_SUP),
+ "Set CR4.LAM_SUP");
+ else
+ report(fault, "Set CR4.LAM_SUP causes #GP");
+
+ fault = test_for_exception(GP_VECTOR, &cr4_clear_lam_sup, NULL);
+ report(!fault, "Clear CR4.LAM_SUP");
+}
+
+static void do_strcpy(void *mem)
+{
+ strcpy((char *)mem, "LAM SUP Test string.");
+}
+
+static inline uint64_t test_tagged_ptr(uint64_t arg1, uint64_t arg2,
+ uint64_t arg3, uint64_t arg4)
+{
+ bool lam_enumerated = !!arg1;
+ int lam_bits = (int)arg2;
+ u64 *ptr = (u64 *)arg3;
+ bool la_57 = !!arg4;
+ bool fault;
+
+ fault = test_for_exception(GP_VECTOR, do_strcpy, ptr);
+ report(!fault, "strcpy to untagged addr");
+
+ ptr = (u64 *)set_metadata((u64)ptr, lam_bits);
+ fault = test_for_exception(GP_VECTOR, do_strcpy, ptr);
+ if (lam_enumerated)
+ report(!fault, "strcpy to tagged addr");
+ else
+ report(fault, "strcpy to tagged addr causes #GP");
...
+
+ if (lam_enumerated && (lam_bits==LAM57_BITS) && !la_57) {
+ ptr = (u64 *)set_metadata((u64)ptr, LAM48_BITS);
+ fault = test_for_exception(GP_VECTOR, do_strcpy, ptr);
+ report(fault, "strcpy to non-LAM-canonical addr causes #GP");
+ }
+
+ return 0;
+}
+
+/* Refer to emulator.c */
+static void do_mov_mmio(void *mem)
+{
+ unsigned long t1, t2;
+
+ // test mov reg, r/m and mov r/m, reg
+ t1 = 0x123456789abcdefull & -1ul;
+ asm volatile("mov %[t1], (%[mem])\n\t"
+ "mov (%[mem]), %[t2]"
+ : [t2]"=r"(t2)
+ : [t1]"r"(t1), [mem]"r"(mem)
+ : "memory");
+}
+
+static inline uint64_t test_tagged_mmio_ptr(uint64_t arg1, uint64_t arg2,
+ uint64_t arg3, uint64_t arg4)
+{
+ bool lam_enumerated = !!arg1;
+ int lam_bits = (int)arg2;
+ u64 *ptr = (u64 *)arg3;
+ bool la_57 = !!arg4;
+ bool fault;
+
+ fault = test_for_exception(GP_VECTOR, do_mov_mmio, ptr);
+ report(!fault, "Access MMIO with untagged addr");
+
+ ptr = (u64 *)set_metadata((u64)ptr, lam_bits);
+ fault = test_for_exception(GP_VECTOR, do_mov_mmio, ptr);
+ if (lam_enumerated)
+ report(!fault, "Access MMIO with tagged addr");
+ else
+ report(fault, "Access MMIO with tagged addr causes #GP");
Maybe make this (and other similar changes) more dense, e.g.,
report(fault != lam_enumerated, "Access MMIO with tagged addr")
+ if (lam_enumerated && (lam_bits==LAM57_BITS) && !la_57) {
+ ptr = (u64 *)set_metadata((u64)ptr, LAM48_BITS);
+ fault = test_for_exception(GP_VECTOR, do_mov_mmio, ptr);
+ report(fault, "Access MMIO with non-LAM-canonical addr"
+ " causes #GP");
don't break long strings.
+ }
please add a comment to explain the intention of this test.
+
+ return 0;
+}
+
+static void do_invlpg(void *mem)
+{
+ invlpg(mem);
+}
+
+static void do_invlpg_fep(void *mem)
+{
+ asm volatile(KVM_FEP "invlpg (%0)" ::"r" (mem) : "memory");
+}
+
+/* invlpg with tagged address is same as NOP, no #GP */
+static void test_invlpg(void *va, bool fep)
+{
+ bool fault;
+ u64 *ptr;
+
+ ptr = (u64 *)set_metadata((u64)va, get_sup_lam_bits());
+ if (fep)
+ fault = test_for_exception(GP_VECTOR, do_invlpg_fep, ptr);
+ else
+ fault = test_for_exception(GP_VECTOR, do_invlpg, ptr);
+
+ report(!fault, "%sINVLPG with tagged addr", fep?"fep: ":"");
+}
+
+static void do_invpcid(void *desc)
+{
+ unsigned long type = 0;
+ struct invpcid_desc *desc_ptr = (struct invpcid_desc *)desc;
+
+ asm volatile("invpcid %0, %1" :
+ : "m" (*desc_ptr), "r" (type)
+ : "memory");
+}
+
+static void test_invpcid(bool lam_enumerated, void *data)
+{
+ struct invpcid_desc *desc_ptr = (struct invpcid_desc *) data;
+ int lam_bits = get_sup_lam_bits();
+ bool fault;
+
+ if (!this_cpu_has(X86_FEATURE_PCID) ||
+ !this_cpu_has(X86_FEATURE_INVPCID)) {
+ report_skip("INVPCID not supported");
+ return;
+ }
+
+ memset(desc_ptr, 0, sizeof(struct invpcid_desc));
+ desc_ptr->addr = (u64)data + 16;
why "+16"? looks you try to avoid invalidating mapping for the descriptor itself.
+
+ fault = test_for_exception(GP_VECTOR, do_invpcid, desc_ptr);
+ report(!fault, "INVPCID: untagged pointer + untagged addr");
+
+ desc_ptr->addr = set_metadata(desc_ptr->addr, lam_bits);
+ fault = test_for_exception(GP_VECTOR, do_invpcid, desc_ptr);
+ report(fault, "INVPCID: untagged pointer + tagged addr causes #GP");
+
+ desc_ptr->addr = (u64)data + 16;
+ desc_ptr = (struct invpcid_desc *)set_metadata((u64)desc_ptr, lam_bits);
+ fault = test_for_exception(GP_VECTOR, do_invpcid, desc_ptr);
+ if (lam_enumerated && (read_cr4() & X86_CR4_LAM_SUP))
+ report(!fault, "INVPCID: tagged pointer + untagged addr");
+ else
+ report(fault, "INVPCID: tagged pointer + untagged addr"
+ " causes #GP");
+
+ desc_ptr = (struct invpcid_desc *)data;
+ desc_ptr->addr = (u64)data + 16;
+ desc_ptr->addr = set_metadata(desc_ptr->addr, lam_bits);
+ desc_ptr = (struct invpcid_desc *)set_metadata((u64)desc_ptr, lam_bits);
+ fault = test_for_exception(GP_VECTOR, do_invpcid, desc_ptr);
+ report(fault, "INVPCID: tagged pointer + tagged addr causes #GP");
+}
+
+static void test_lam_sup(bool lam_enumerated, bool fep_available)
+{
+ void *vaddr, *vaddr_mmio;
+ phys_addr_t paddr;
+ bool fault;
+ bool la_57 = read_cr4() & X86_CR4_LA57;
+ int lam_bits = get_sup_lam_bits();
+
+ 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(lam_enumerated);
+
+ /* Set for the following LAM_SUP tests */
+ if (lam_enumerated) {
+ fault = test_for_exception(GP_VECTOR, &cr4_set_lam_sup, NULL);
+ report(!fault && (read_cr4() & X86_CR4_LAM_SUP),
+ "Set CR4.LAM_SUP");
+ }
+
+ test_tagged_ptr(lam_enumerated, lam_bits, (u64)vaddr, la_57);
+ test_tagged_mmio_ptr(lam_enumerated, lam_bits, (u64)vaddr_mmio, la_57);
+ test_invlpg(vaddr, false);
+ test_invpcid(lam_enumerated, vaddr);
+
+ if (fep_available)
+ test_invlpg(vaddr, true);
+}
+
+int main(int ac, char **av)
+{
+ bool lam_enumerated;
+ bool fep_available = is_fep_available();
+
+ setup_vm();
+
+ lam_enumerated = this_cpu_has(X86_FEATURE_LAM);
has_lam?
+ if (!lam_enumerated)
+ report_info("This CPU doesn't support LAM feature\n");
+ else
+ report_info("This CPU supports LAM feature\n");
+
+ if (!fep_available)
+ report_skip("Skipping tests the forced emulation, "
+ "use kvm.force_emulation_prefix=1 to enable\n");
+
+ test_lam_sup(lam_enumerated, fep_available);
+
+ return report_summary();
+}
diff --git a/x86/unittests.cfg b/x86/unittests.cfg
index f324e32..34b09eb 100644
--- a/x86/unittests.cfg
+++ b/x86/unittests.cfg
@@ -478,3 +478,13 @@ 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
--
2.25.1
