[PATCH v4 7/7] xen/arm: Sanitize CTR_EL0

[Bertrand Marquis <bertrand.marquis@xxxxxxx>]

Sanitize CTR_EL0 value between cores and taint Xen if incompatible
values are found.

In the case of different i-cache types, the sanitize ctr_el0 will have a
sanitize value but this is currently not used or exposed to guest which
are seeing the original ctr_el0 value.

Use the opportunity to rename CTR_L1Ip to use an upper case name like
Linux does.
The patch is also defining ICACHE_POLICY_xxx instead of only having
CTR_L1IP_xxx to sync the definitions with Linux and is updating the code
using those accordingly (arm32 setup).

On platforms with only the same type of cores, this patch should not
modify the current Xen behaviour.

Signed-off-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
Changes in v4: Remove TID2 support and handling of corresponding
register emulation in vcpreg/vsysreg.
Changes in v3: none
Change in v2: Patch introduced in v2
---
 xen/arch/arm/arm64/cpufeature.c  |  6 ++----
 xen/arch/arm/cpufeature.c        |  2 ++
 xen/arch/arm/setup.c             |  2 +-
 xen/include/asm-arm/cpufeature.h |  9 +++++++++
 xen/include/asm-arm/processor.h  | 18 +++++++++++++++---
 5 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/arm64/cpufeature.c b/xen/arch/arm/arm64/cpufeature.c
index d4679f5df3..6e5d30dc7b 100644
--- a/xen/arch/arm/arm64/cpufeature.c
+++ b/xen/arch/arm/arm64/cpufeature.c
@@ -275,9 +275,6 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
        ARM64_FTR_END,
 };
 
-#if 0
-/* TODO: use this to sanitize the cache line size among cores */
-
 static const struct arm64_ftr_bits ftr_ctr[] = {
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 31, 1, 1), /* RES1 */
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_DIC_SHIFT, 
1, 1),
@@ -294,7 +291,6 @@ static const struct arm64_ftr_bits ftr_ctr[] = {
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 
CTR_IMINLINE_SHIFT, 4, 0),
        ARM64_FTR_END,
 };
-#endif
 
 static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
        S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 
ID_MMFR0_INNERSHR_SHIFT, 4, 0xf),
@@ -606,6 +602,8 @@ void update_system_features(const struct cpuinfo_arm *new)
         */
        SANITIZE_REG(dczid, 0, dczid);
 
+       SANITIZE_REG(ctr, 0, ctr);
+
        if ( cpu_feature64_has_el0_32(&system_cpuinfo) )
        {
                SANITIZE_ID_REG(pfr32, 0, pfr0);
diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
index 113f20f601..6e51f530a8 100644
--- a/xen/arch/arm/cpufeature.c
+++ b/xen/arch/arm/cpufeature.c
@@ -127,6 +127,8 @@ void identify_cpu(struct cpuinfo_arm *c)
 
     c->dczid.bits[0] = READ_SYSREG(DCZID_EL0);
 
+    c->ctr.bits[0] = READ_SYSREG(CTR_EL0);
+
     aarch32_el0 = cpu_feature64_has_el0_32(c);
 #endif
 
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 4ab13d0fbe..49dc90d198 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -650,7 +650,7 @@ static void __init setup_mm(void)
         panic("No memory bank\n");
 
     /* We only supports instruction caches implementing the IVIPT extension. */
-    if ( ((ctr >> CTR_L1Ip_SHIFT) & CTR_L1Ip_MASK) == CTR_L1Ip_AIVIVT )
+    if ( ((ctr >> CTR_L1IP_SHIFT) & CTR_L1IP_MASK) == ICACHE_POLICY_AIVIVT )
         panic("AIVIVT instruction cache not supported\n");
 
     init_pdx();
diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 5219fd3bab..cab89ee142 100644
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -267,6 +267,14 @@ struct cpuinfo_arm {
         register_t bits[1];
     } dczid;
 
+    /*
+     * CTR is only used to check for different cache types or policies and
+     * taint Xen in this case
+     */
+    struct {
+        register_t bits[1];
+    } ctr;
+
 #endif
 
     /*
@@ -339,6 +347,7 @@ extern struct cpuinfo_arm system_cpuinfo;
 extern void identify_cpu(struct cpuinfo_arm *);
 
 #ifdef CONFIG_ARM_64
+
 extern void update_system_features(const struct cpuinfo_arm *);
 #else
 static inline void update_system_features(const struct cpuinfo_arm *cpuinfo)
diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index 2058b69447..8ab2940f68 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -7,9 +7,21 @@
 #include <public/arch-arm.h>
 
 /* CTR Cache Type Register */
-#define CTR_L1Ip_MASK       0x3
-#define CTR_L1Ip_SHIFT      14
-#define CTR_L1Ip_AIVIVT     0x1
+#define CTR_L1IP_MASK       0x3
+#define CTR_L1IP_SHIFT      14
+#define CTR_DMINLINE_SHIFT  16
+#define CTR_IMINLINE_SHIFT  0
+#define CTR_IMINLINE_MASK   0xf
+#define CTR_ERG_SHIFT       20
+#define CTR_CWG_SHIFT       24
+#define CTR_CWG_MASK        15
+#define CTR_IDC_SHIFT       28
+#define CTR_DIC_SHIFT       29
+
+#define ICACHE_POLICY_VPIPT  0
+#define ICACHE_POLICY_AIVIVT 1
+#define ICACHE_POLICY_VIPT   2
+#define ICACHE_POLICY_PIPT   3
 
 /* MIDR Main ID Register */
 #define MIDR_REVISION_MASK      0xf
-- 
2.17.1