On POWER9 the ibm,client-architecture-support (CAS) negotiation process
has been updated to change how the host to guest negotiation is done for
the new hash/radix mmu as well as the nest mmu, process tables and guest
translation shootdown (GTSE).
The host tells the guest which options it supports in
ibm,arch-vec-5-platform-support. The guest then chooses a subset of these
to request in the CAS call and these are agreed to in the
ibm,architecture-vec-5 property of the chosen node.
Thus we read ibm,arch-vec-5-platform-support and make our selection before
calling CAS. We then parse the ibm,architecture-vec-5 property of the
chosen node to check whether we should run as hash or radix.
ibm,arch-vec-5-platform-support format:
index value pairs: <index, val> ... <index, val>
index: Option vector 5 byte number
val: Some representation of supported values
Signed-off-by: Suraj Jitindar Singh <sjitindarsi...@gmail.com>
---
V1 -> V2:
- Fix error where whole byte was compared for mmu support instead of only the
first two bytes
- Break platform support parsing into multiple functions for clarity
- Instead of printing WARNING: messages on old hypervisors change to a debug
message
---
arch/powerpc/include/asm/prom.h | 17 ++++--
arch/powerpc/kernel/prom_init.c | 120 ++++++++++++++++++++++++++++++++++++++--
arch/powerpc/mm/init_64.c | 36 ++++++++++--
3 files changed, 157 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
index 8af2546..d838b9d 100644
--- a/arch/powerpc/include/asm/prom.h
+++ b/arch/powerpc/include/asm/prom.h
@@ -158,12 +158,17 @@ struct of_drconf_cell {
#define OV5_PFO_HW_ENCR 0x1120 /* PFO Encryption Accelerator */
#define OV5_SUB_PROCESSORS 0x1501 /* 1,2,or 4 Sub-Processors supported */
#define OV5_XIVE_EXPLOIT 0x1701 /* XIVE exploitation supported */
-#define OV5_MMU_RADIX_300 0x1880 /* ISA v3.00 radix MMU supported */
-#define OV5_MMU_HASH_300 0x1840 /* ISA v3.00 hash MMU supported */
-#define OV5_MMU_SEGM_RADIX 0x1820 /* radix mode (no segmentation) */
-#define OV5_MMU_PROC_TBL 0x1810 /* hcall selects SLB or proc table */
-#define OV5_MMU_SLB 0x1800 /* always use SLB */
-#define OV5_MMU_GTSE 0x1808 /* Guest translation shootdown */
+/* MMU Base Architecture */
+#define OV5_MMU_SUPPORT 0x18C0 /* MMU Mode Support Mask */
+#define OV5_MMU_HASH 0x00 /* Hash MMU Only */
+#define OV5_MMU_RADIX 0x40 /* Radix MMU Only */
+#define OV5_MMU_EITHER 0x80 /* Hash or Radix Supported */
+#define OV5_NMMU 0x1820 /* Nest MMU Available */
+/* Hash Table Extensions */
+#define OV5_HASH_SEG_TBL 0x1980 /* In Memory Segment Tables Available */
+#define OV5_HASH_GTSE 0x1940 /* Guest Translation Shoot Down Avail */
+/* Radix Table Extensions */
+#define OV5_RADIX_GTSE 0x1A40 /* Guest Translation Shoot Down Avail */
/* Option Vector 6: IBM PAPR hints */
#define OV6_LINUX 0x02 /* Linux is our OS */
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 37b5a29..08cd1b8 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -168,6 +168,14 @@ static unsigned long __initdata prom_tce_alloc_start;
static unsigned long __initdata prom_tce_alloc_end;
#endif
+static bool __initdata prom_radix_disable;
+
+struct platform_support {
+ bool hash_mmu;
+ bool radix_mmu;
+ bool radix_gtse;
+};
+
/* Platforms codes are now obsolete in the kernel. Now only used within this
* file and ultimately gone too. Feel free to change them if you need, they
* are not shared with anything outside of this file anymore
@@ -626,6 +634,12 @@ static void __init early_cmdline_parse(void)
prom_memory_limit = ALIGN(prom_memory_limit, 0x1000000);
#endif
}
+
+ opt = strstr(prom_cmd_line, "disable_radix");
+ if (opt) {
+ prom_debug("Radix disabled from cmdline\n");
+ prom_radix_disable = true;
+ }
}
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
@@ -693,8 +707,10 @@ struct option_vector5 {
__be16 reserved3;
u8 subprocessors;
u8 byte22;
- u8 intarch;
+ u8 xive;
u8 mmu;
+ u8 hash_ext;
+ u8 radix_ext;
} __packed;
struct option_vector6 {
@@ -849,9 +865,10 @@ struct ibm_arch_vec __cacheline_aligned
ibm_architecture_vec = {
.reserved2 = 0,
.reserved3 = 0,
.subprocessors = 1,
- .intarch = 0,
- .mmu = OV5_FEAT(OV5_MMU_RADIX_300) | OV5_FEAT(OV5_MMU_HASH_300)
|
- OV5_FEAT(OV5_MMU_PROC_TBL) | OV5_FEAT(OV5_MMU_GTSE),
+ .xive = 0,
+ .mmu = 0,
+ .hash_ext = 0,
+ .radix_ext = 0,
},
/* option vector 6: IBM PAPR hints */
@@ -990,6 +1007,98 @@ static int __init prom_count_smt_threads(void)
}
+static void __init prom_parse_mmu_model(u8 val,
+ struct platform_support *support)
+{
+ switch (val) {
+ case OV5_MMU_EITHER: /* Either Available */
+ prom_debug("MMU - either supported\n");
+ support->radix_mmu = !prom_radix_disable;
+ support->hash_mmu = true;
+ break;
+ case OV5_MMU_RADIX: /* Only Radix */
+ prom_debug("MMU - radix only\n");
+ if (prom_radix_disable) {
+ /*
+ * If we __have__ to do radix, we're better off ignoring
+ * the command line rather than not booting.
+ */
+ prom_printf("WARNING: Ignoring cmdline option
disable_radix\n");
+ }
+ support->radix_mmu = true;
+ break;
+ case OV5_MMU_HASH:
+ prom_debug("MMU - hash only\n");
+ support->hash_mmu = true;
+ break;
+ default:
+ prom_debug("Unknown mmu support option: 0x%x\n", val);
+ break;
+ }
+}
+
+static void __init prom_parse_platform_support(u8 index, u8 val,
+ struct platform_support *support)
+{
+ switch (index) {
+ case OV5_INDX(OV5_XIVE_EXPLOIT): /* Unimplemented - Ignore */
+ break;
+ case OV5_INDX(OV5_MMU_SUPPORT): /* MMU Model */
+ prom_parse_mmu_model(val & OV5_FEAT(OV5_MMU_SUPPORT), support);
+ break;
+ case OV5_INDX(OV5_HASH_SEG_TBL): /* Unimplemented - Ignore */
+ break;
+ case OV5_INDX(OV5_RADIX_GTSE): /* Radix Extensions */
+ if (val & OV5_FEAT(OV5_RADIX_GTSE)) {
+ prom_debug("Radix - GTSE supported\n");
+ support->radix_gtse = true;
+ }
+ break;
+ default:
+ prom_debug("Unknown platform support option above\n");
+ break;
+ }
+}
+
+static void __init prom_check_platform_support(void)
+{
+ struct platform_support supported = {
+ .hash_mmu = false,
+ .radix_mmu = false,
+ .radix_gtse = false
+ };
+ int prop_len = prom_getproplen(prom.chosen,
+ "ibm,arch-vec-5-platform-support");
+ if (prop_len > 1) {
+ int i;
+ u8 vec[prop_len];
+ prom_debug("Found ibm,arch-vec-5-platform-support, len: %d\n",
+ prop_len);
+ prom_getprop(prom.chosen, "ibm,arch-vec-5-platform-support",
+ &vec, sizeof(vec));
+ for (i = 0; i < prop_len; i += 2) {
+ prom_debug("%d: index = 0x%x val = 0x%x\n", i / 2
+ , vec[i]
+ , vec[i + 1]);
+ prom_parse_platform_support(vec[i], vec[i + 1],
+ &supported);
+ }
+ }
+
+ if (supported.radix_mmu && supported.radix_gtse) {
+ /* Radix preferred - but we require GTSE for now */
+ prom_debug("Asking for radix with GTSE\n");
+ ibm_architecture_vec.vec5.mmu = OV5_FEAT(OV5_MMU_RADIX);
+ ibm_architecture_vec.vec5.radix_ext = OV5_FEAT(OV5_RADIX_GTSE);
+ } else if (supported.hash_mmu) {
+ /* Default to hash mmu (if we can) */
+ prom_debug("Asking for hash\n");
+ ibm_architecture_vec.vec5.mmu = OV5_FEAT(OV5_MMU_HASH);
+ } else {
+ /* We're probably on a legacy hypervisor */
+ prom_debug("Assuming legacy hash support\n");
+ }
+}
static void __init prom_send_capabilities(void)
{
@@ -997,6 +1106,9 @@ static void __init prom_send_capabilities(void)
prom_arg_t ret;
u32 cores;
+ /* Check ibm,arch-vec-5-platform-support and fixup vec5 if required */
+ prom_check_platform_support();
+
root = call_prom("open", 1, 1, ADDR("/"));
if (root != 0) {
/* We need to tell the FW about the number of cores we support.
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 6aa3b76..9be9920 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -356,18 +356,42 @@ static void early_check_vec5(void)
unsigned long root, chosen;
int size;
const u8 *vec5;
+ u8 mmu_supported;
root = of_get_flat_dt_root();
chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
- if (chosen == -FDT_ERR_NOTFOUND)
+ if (chosen == -FDT_ERR_NOTFOUND) {
+ cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
return;
+ }
vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size);
- if (!vec5)
+ if (!vec5) {
+ cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
return;
- if (size <= OV5_INDX(OV5_MMU_RADIX_300) ||
- !(vec5[OV5_INDX(OV5_MMU_RADIX_300)] & OV5_FEAT(OV5_MMU_RADIX_300)))
- /* Hypervisor doesn't support radix */
+ }
+ if (size <= OV5_INDX(OV5_MMU_SUPPORT)) {
cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
+ return;
+ }
+
+ /* Check for supported configuration */
+ mmu_supported = vec5[OV5_INDX(OV5_MMU_SUPPORT)] &
+ OV5_FEAT(OV5_MMU_SUPPORT);
+ if (mmu_supported == OV5_FEAT(OV5_MMU_RADIX)) {
+ /* Hypervisor only supports radix - check enabled && GTSE */
+ if (!early_radix_enabled()) {
+ pr_warn("WARNING: Ignoring cmdline option
disable_radix\n");
+ }
+ if (!(vec5[OV5_INDX(OV5_RADIX_GTSE)] &
+ OV5_FEAT(OV5_RADIX_GTSE))) {
+ pr_warn("WARNING: Hypervisor doesn't support RADIX with
GTSE\n");
+ }
+ /* Do radix anyway - the hypervisor said we had to */
+ cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX;
+ } else if (mmu_supported == OV5_FEAT(OV5_MMU_HASH)) {
+ /* Hypervisor only supports hash - disable radix */
+ cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
+ }
}
void __init mmu_early_init_devtree(void)
@@ -383,7 +407,7 @@ void __init mmu_early_init_devtree(void)
* even though the ibm,architecture-vec-5 property created by
* skiboot doesn't have the necessary bits set.
*/
- if (early_radix_enabled() && !(mfmsr() & MSR_HV))
+ if (!(mfmsr() & MSR_HV))
early_check_vec5();
if (early_radix_enabled())
--
2.5.5
