diff mbox series

[kernel,v2,3/4] powerpc/pseries/iommu: Separate FW_FEATURE_MULTITCE to put/stuff features

Message ID 20191216041924.42318-4-aik@ozlabs.ru (mailing list archive)
State Accepted
Commit 17a0364cb07c173f64cefe973a93b8dbd9c61795
Headers show
Series Enable IOMMU support for pseries Secure VMs | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (69b349a06f979f2c93a5d6902e57e3e19dcd0475)
snowpatch_ozlabs/checkpatch warning total: 0 errors, 0 warnings, 1 checks, 70 lines checked

Commit Message

Alexey Kardashevskiy Dec. 16, 2019, 4:19 a.m. UTC 
H_PUT_TCE_INDIRECT allows packing up to 512 TCE updates into a single
hypercall; H_STUFF_TCE can clear lots in a single hypercall too.

However, unlike H_STUFF_TCE (which writes the same TCE to all entries),
H_PUT_TCE_INDIRECT uses a 4K page with new TCEs. In a secure VM
environment this means sharing a secure VM page with a hypervisor which
we would rather avoid.

This splits the FW_FEATURE_MULTITCE feature into FW_FEATURE_PUT_TCE_IND
and FW_FEATURE_STUFF_TCE. "hcall-multi-tce" in
the "/rtas/ibm,hypertas-functions" device tree property sets both;
the "multitce=off" kernel command line parameter disables both.

This should not cause behavioural change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v2
* instead of checking for secure VM here and there, this adds a new
FW feature
* moved SVM enablement to a separate patch
---
 arch/powerpc/include/asm/firmware.h       |  6 ++++--
 arch/powerpc/platforms/pseries/firmware.c |  3 ++-
 arch/powerpc/platforms/pseries/iommu.c    | 12 +++++++-----
 3 files changed, 13 insertions(+), 8 deletions(-)

Comments

Thiago Jung Bauermann Dec. 16, 2019, 11:19 p.m. UTC | #1 
Alexey Kardashevskiy <aik@ozlabs.ru> writes:

> H_PUT_TCE_INDIRECT allows packing up to 512 TCE updates into a single
> hypercall; H_STUFF_TCE can clear lots in a single hypercall too.
>
> However, unlike H_STUFF_TCE (which writes the same TCE to all entries),
> H_PUT_TCE_INDIRECT uses a 4K page with new TCEs. In a secure VM
> environment this means sharing a secure VM page with a hypervisor which
> we would rather avoid.
>
> This splits the FW_FEATURE_MULTITCE feature into FW_FEATURE_PUT_TCE_IND
> and FW_FEATURE_STUFF_TCE. "hcall-multi-tce" in
> the "/rtas/ibm,hypertas-functions" device tree property sets both;
> the "multitce=off" kernel command line parameter disables both.
>
> This should not cause behavioural change.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Tested-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Ram Pai Jan. 2, 2020, 10:24 p.m. UTC | #2 
On Mon, Dec 16, 2019 at 03:19:23PM +1100, Alexey Kardashevskiy wrote:
> H_PUT_TCE_INDIRECT allows packing up to 512 TCE updates into a single
> hypercall; H_STUFF_TCE can clear lots in a single hypercall too.
> 
> However, unlike H_STUFF_TCE (which writes the same TCE to all entries),
> H_PUT_TCE_INDIRECT uses a 4K page with new TCEs. In a secure VM
> environment this means sharing a secure VM page with a hypervisor which
> we would rather avoid.
> 
> This splits the FW_FEATURE_MULTITCE feature into FW_FEATURE_PUT_TCE_IND

Can FW_FEATURE_PUT_TCE_IND be made FW_FEATURE_PUT_TCE_INDIRECT?
It conveys the meaning a bit better than FW_FEATURE_PUT_TCE_IND.

This patch is a good optimization. 

Reviewed-by: Ram Pai <linuxram@us.ibm.com>

Thanks,
RP
> -- 

snip..

> 2.17.1
diff mbox series

Patch

diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index b3e214a97f3a..ca33f4ef6cb4 100644
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -33,7 +33,7 @@ 
 #define FW_FEATURE_LLAN		ASM_CONST(0x0000000000010000)
 #define FW_FEATURE_BULK_REMOVE	ASM_CONST(0x0000000000020000)
 #define FW_FEATURE_XDABR	ASM_CONST(0x0000000000040000)
-#define FW_FEATURE_MULTITCE	ASM_CONST(0x0000000000080000)
+#define FW_FEATURE_PUT_TCE_IND	ASM_CONST(0x0000000000080000)
 #define FW_FEATURE_SPLPAR	ASM_CONST(0x0000000000100000)
 #define FW_FEATURE_LPAR		ASM_CONST(0x0000000000400000)
 #define FW_FEATURE_PS3_LV1	ASM_CONST(0x0000000000800000)
@@ -51,6 +51,7 @@ 
 #define FW_FEATURE_BLOCK_REMOVE ASM_CONST(0x0000001000000000)
 #define FW_FEATURE_PAPR_SCM 	ASM_CONST(0x0000002000000000)
 #define FW_FEATURE_ULTRAVISOR	ASM_CONST(0x0000004000000000)
+#define FW_FEATURE_STUFF_TCE	ASM_CONST(0x0000008000000000)
 
 #ifndef __ASSEMBLY__
 
@@ -63,7 +64,8 @@  enum {
 		FW_FEATURE_MIGRATE | FW_FEATURE_PERFMON | FW_FEATURE_CRQ |
 		FW_FEATURE_VIO | FW_FEATURE_RDMA | FW_FEATURE_LLAN |
 		FW_FEATURE_BULK_REMOVE | FW_FEATURE_XDABR |
-		FW_FEATURE_MULTITCE | FW_FEATURE_SPLPAR | FW_FEATURE_LPAR |
+		FW_FEATURE_PUT_TCE_IND | FW_FEATURE_STUFF_TCE |
+		FW_FEATURE_SPLPAR | FW_FEATURE_LPAR |
 		FW_FEATURE_CMO | FW_FEATURE_VPHN | FW_FEATURE_XCMO |
 		FW_FEATURE_SET_MODE | FW_FEATURE_BEST_ENERGY |
 		FW_FEATURE_TYPE1_AFFINITY | FW_FEATURE_PRRN |
diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c
index d4a8f1702417..d3acff23f2e3 100644
--- a/arch/powerpc/platforms/pseries/firmware.c
+++ b/arch/powerpc/platforms/pseries/firmware.c
@@ -55,7 +55,8 @@  hypertas_fw_features_table[] = {
 	{FW_FEATURE_LLAN,		"hcall-lLAN"},
 	{FW_FEATURE_BULK_REMOVE,	"hcall-bulk"},
 	{FW_FEATURE_XDABR,		"hcall-xdabr"},
-	{FW_FEATURE_MULTITCE,		"hcall-multi-tce"},
+	{FW_FEATURE_PUT_TCE_IND | FW_FEATURE_STUFF_TCE,
+					"hcall-multi-tce"},
 	{FW_FEATURE_SPLPAR,		"hcall-splpar"},
 	{FW_FEATURE_VPHN,		"hcall-vphn"},
 	{FW_FEATURE_SET_MODE,		"hcall-set-mode"},
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index f6e9b87c82fc..07b91938c3cc 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -192,7 +192,7 @@  static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 	int ret = 0;
 	unsigned long flags;
 
-	if ((npages == 1) || !firmware_has_feature(FW_FEATURE_MULTITCE)) {
+	if ((npages == 1) || !firmware_has_feature(FW_FEATURE_PUT_TCE_IND)) {
 		return tce_build_pSeriesLP(tbl->it_index, tcenum,
 					   tbl->it_page_shift, npages, uaddr,
 		                           direction, attrs);
@@ -286,7 +286,7 @@  static void tce_freemulti_pSeriesLP(struct iommu_table *tbl, long tcenum, long n
 {
 	u64 rc;
 
-	if (!firmware_has_feature(FW_FEATURE_MULTITCE))
+	if (!firmware_has_feature(FW_FEATURE_STUFF_TCE))
 		return tce_free_pSeriesLP(tbl->it_index, tcenum, npages);
 
 	rc = plpar_tce_stuff((u64)tbl->it_index, (u64)tcenum << 12, 0, npages);
@@ -402,7 +402,7 @@  static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
 	u64 rc = 0;
 	long l, limit;
 
-	if (!firmware_has_feature(FW_FEATURE_MULTITCE)) {
+	if (!firmware_has_feature(FW_FEATURE_PUT_TCE_IND)) {
 		unsigned long tceshift = be32_to_cpu(maprange->tce_shift);
 		unsigned long dmastart = (start_pfn << PAGE_SHIFT) +
 				be64_to_cpu(maprange->dma_base);
@@ -1342,9 +1342,11 @@  static int __init disable_multitce(char *str)
 {
 	if (strcmp(str, "off") == 0 &&
 	    firmware_has_feature(FW_FEATURE_LPAR) &&
-	    firmware_has_feature(FW_FEATURE_MULTITCE)) {
+	    (firmware_has_feature(FW_FEATURE_PUT_TCE_IND) ||
+	     firmware_has_feature(FW_FEATURE_STUFF_TCE))) {
 		printk(KERN_INFO "Disabling MULTITCE firmware feature\n");
-		powerpc_firmware_features &= ~FW_FEATURE_MULTITCE;
+		powerpc_firmware_features &=
+			~(FW_FEATURE_PUT_TCE_IND | FW_FEATURE_STUFF_TCE);
 	}
 	return 1;
 }