[kvm-unit-tests PATCH v2 3/4] x86: Add test cases for LAM_{U48,U57}

[Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>]

This unit test covers:
1. CR3 LAM bits toggle has expected behavior according to LAM status.
2. Memory access using strcpy() with user mode address containing LAM
   meta data, behave as expected per LAM status.
3. MMIO memory access with user mode address containing LAM meta data,
   behave as expected per LAM status.

Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
---
 lib/x86/processor.h |  2 ++
 x86/lam.c           | 46 ++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index 4bb8cd7..a181e0b 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -56,7 +56,9 @@
 
 #define X86_CR3_PCID_MASK	GENMASK(11, 0)
 #define X86_CR3_LAM_U57_BIT	(61)
+#define X86_CR3_LAM_U57		BIT_ULL(X86_CR3_LAM_U57_BIT)
 #define X86_CR3_LAM_U48_BIT	(62)
+#define X86_CR3_LAM_U48		BIT_ULL(X86_CR3_LAM_U48_BIT)
 
 #define X86_CR4_VME_BIT		(0)
 #define X86_CR4_VME		BIT(X86_CR4_VME_BIT)
diff --git a/x86/lam.c b/x86/lam.c
index a5f4e51..8945440 100644
--- a/x86/lam.c
+++ b/x86/lam.c
@@ -1,5 +1,5 @@
 /*
- * Intel LAM_SUP unit test
+ * Intel LAM unit test
  *
  * Copyright (C) 2023 Intel
  *
@@ -18,11 +18,13 @@
 #include "vm.h"
 #include "asm/io.h"
 #include "ioram.h"
+#include "usermode.h"
 
 #define LAM57_BITS 6
 #define LAM48_BITS 15
 #define LAM57_MASK	GENMASK_ULL(62, 57)
 #define LAM48_MASK	GENMASK_ULL(62, 48)
+#define CR3_LAM_BITS_MASK (X86_CR3_LAM_U48 | X86_CR3_LAM_U57)
 
 struct invpcid_desc {
     u64 pcid : 12;
@@ -273,6 +275,47 @@ static void test_lam_sup(bool lam_enumerated, bool fep_available)
 		test_invlpg(vaddr, true);
 }
 
+static void test_lam_user(bool lam_enumerated)
+{
+	unsigned long cr3;
+	bool is_la57;
+	unsigned r;
+	bool raised_vector = false;
+	phys_addr_t paddr;
+
+	paddr = virt_to_phys(alloc_page());
+	install_page((void *)(read_cr3()& ~CR3_LAM_BITS_MASK), paddr, (void *)paddr);
+	install_page((void *)(read_cr3()& ~CR3_LAM_BITS_MASK), IORAM_BASE_PHYS,
+		     (void *)IORAM_BASE_PHYS);
+
+	cr3 = read_cr3();
+	is_la57 = !!(read_cr4() & X86_CR4_LA57);
+
+	/* Test LAM_U48 */
+	if(lam_enumerated) {
+		r = write_cr3_safe((cr3 & ~X86_CR3_LAM_U57) | X86_CR3_LAM_U48);
+		report(r==0 && ((read_cr3() & CR3_LAM_BITS_MASK) == X86_CR3_LAM_U48),
+		       "Set LAM_U48");
+	}
+
+	run_in_user((usermode_func)test_tagged_ptr, GP_VECTOR, lam_enumerated,
+		    LAM48_BITS, paddr, is_la57, &raised_vector);
+	run_in_user((usermode_func)test_tagged_mmio_ptr, GP_VECTOR, lam_enumerated,
+		    LAM48_BITS, IORAM_BASE_PHYS, is_la57, &raised_vector);
+
+
+	/* Test LAM_U57 */
+	if(lam_enumerated) {
+		r = write_cr3_safe(cr3 | X86_CR3_LAM_U57);
+		report(r==0 && (read_cr3() & X86_CR3_LAM_U57), "Set LAM_U57");
+	}
+
+	run_in_user((usermode_func)test_tagged_ptr, GP_VECTOR, lam_enumerated,
+		    LAM57_BITS, paddr, is_la57, &raised_vector);
+	run_in_user((usermode_func)test_tagged_mmio_ptr, GP_VECTOR, lam_enumerated,
+		    LAM57_BITS, IORAM_BASE_PHYS, is_la57, &raised_vector);
+}
+
 int main(int ac, char **av)
 {
 	bool lam_enumerated;
@@ -291,6 +334,7 @@ int main(int ac, char **av)
 			    "use kvm.force_emulation_prefix=1 to enable\n");
 
 	test_lam_sup(lam_enumerated, fep_available);
+	test_lam_user(lam_enumerated);
 
 	return report_summary();
 }
-- 
2.25.1