[V3 PATCH 08/16] powerpc/pseries/VAS: Implement allocate/modify/deallocate HCALLS

Haren Myneni
2021-04-17T21:07:42Z

This patch adds the following HCALLs which are used to allocate,
modify and deallocate VAS windows.

H_ALLOCATE_VAS_WINDOW: Allocate VAS window
H_DEALLOCATE_VAS_WINDOW: Close VAS window
H_MODIFY_VAS_WINDOW: Setup window before using

Also adds phyp call (H_QUERY_VAS_CAPABILITIES) to get all VAS
capabilities that phyp provides.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
arch/powerpc/platforms/pseries/vas.c | 217 +++++++++++++++++++++++++++
1 file changed, 217 insertions(+)
create mode 100644 arch/powerpc/platforms/pseries/vas.c

diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
new file mode 100644
index 000000000000..06960151477c
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2020-21 IBM Corp.
+ */
+
+#define pr_fmt(fmt) "vas: " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/sched/mm.h>
+#include <linux/mmu_context.h>
+#include <asm/hvcall.h>
+#include <asm/hvconsole.h>
+#include <asm/machdep.h>
+#include <asm/plpar_wrappers.h>
+#include <asm/vas.h>
+#include "vas.h"
+
+#define VAS_INVALID_WIN_ADDRESS 0xFFFFFFFFFFFFFFFFul
+#define VAS_DEFAULT_DOMAIN_ID 0xFFFFFFFFFFFFFFFFul
+/* Authority Mask Register (AMR) value is not supported in */
+/* linux implementation. So pass '0' to modify window HCALL */
+#define VAS_AMR_VALUE 0
+/* phyp allows one credit per window right now */
+#define DEF_WIN_CREDS 1
+
+static int64_t hcall_return_busy_check(int64_t rc)
+{
+ /* Check if we are stalled for some time */
+ if (H_IS_LONG_BUSY(rc)) {
+ msleep(get_longbusy_msecs(rc));
+ rc = H_BUSY;
+ } else if (rc == H_BUSY) {
+ cond_resched();
+ }
+
+ return rc;
+}
+
+/*
+ * Allocate VAS window HCALL
+ */
+static int plpar_vas_allocate_window(struct vas_window *win, u64 *domain,
+ u8 wintype, u16 credits)
+{
+ long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
+ int64_t rc;
+
+ do {
+ rc = plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, wintype,
+ credits, domain[0], domain[1], domain[2],
+ domain[3], domain[4], domain[5]);
+
+ rc = hcall_return_busy_check(rc);
+ } while (rc == H_BUSY);
+
+ switch (rc) {
+ case H_SUCCESS:
+ win->winid = retbuf[0];
+ win->lpar.win_addr = retbuf[1];
+ win->lpar.complete_irq = retbuf[2];
+ win->lpar.fault_irq = retbuf[3];
+ if (win->lpar.win_addr == VAS_INVALID_WIN_ADDRESS) {
+ pr_err("HCALL(%x): COPY/PASTE is not supported\n",
+ H_ALLOCATE_VAS_WINDOW);
+ return -ENOTSUPP;
+ }
+ return 0;
+ case H_PARAMETER:
+ pr_err("HCALL(%x): Invalid window type (%u)\n",
+ H_ALLOCATE_VAS_WINDOW, wintype);
+ return -EINVAL;
+ case H_P2:
+ pr_err("HCALL(%x): Credits(%u) exceed maximum window credits\n",
+ H_ALLOCATE_VAS_WINDOW, credits);
+ return -EINVAL;
+ case H_COP_HW:
+ pr_err("HCALL(%x): User-mode COPY/PASTE is not supported\n",
+ H_ALLOCATE_VAS_WINDOW);
+ return -ENOTSUPP;
+ case H_RESOURCE:
+ pr_err("HCALL(%x): LPAR credit limit exceeds window limit\n",
+ H_ALLOCATE_VAS_WINDOW);
+ return -EPERM;
+ case H_CONSTRAINED:
+ pr_err("HCALL(%x): Credits (%u) are not available\n",
+ H_ALLOCATE_VAS_WINDOW, credits);
+ return -EPERM;
+ default:
+ pr_err("HCALL(%x): Unexpected error %lld\n",
+ H_ALLOCATE_VAS_WINDOW, rc);
+ return -EIO;
+ }
+}
+
+/*
+ * Deallocate VAS window HCALL.
+ */
+static int plpar_vas_deallocate_window(u64 winid)
+{
+ int64_t rc;
+
+ do {
+ rc = plpar_hcall_norets(H_DEALLOCATE_VAS_WINDOW, winid);
+
+ rc = hcall_return_busy_check(rc);
+ } while (rc == H_BUSY);
+
+ switch (rc) {
+ case H_SUCCESS:
+ return 0;
+ case H_PARAMETER:
+ pr_err("HCALL(%x): Invalid window ID %llu\n",
+ H_DEALLOCATE_VAS_WINDOW, winid);
+ return -EINVAL;
+ case H_STATE:
+ pr_err("HCALL(%x): Window(%llu): Invalid page table entries\n",
+ H_DEALLOCATE_VAS_WINDOW, winid);
+ return -EPERM;
+ default:
+ pr_err("HCALL(%x): Unexpected error %lld for window(%llu)\n",
+ H_DEALLOCATE_VAS_WINDOW, rc, winid);
+ return -EIO;
+ }
+}
+
+/*
+ * Modify VAS window.
+ * After the window is opened with allocate window HCALL, configure it
+ * with flags and LPAR PID before using.
+ */
+static int plpar_vas_modify_window(struct vas_window *win)
+{
+ int64_t rc;
+ u32 lpid = mfspr(SPRN_PID);
+
+ /*
+ * AMR value is not supported in Linux implementation
+ * phyp ignores it if 0 is passed.
+ */
+ do {
+ rc = plpar_hcall_norets(H_MODIFY_VAS_WINDOW, win->winid,
+ lpid, 0, VAS_MOD_WIN_FLAGS,
+ VAS_AMR_VALUE);
+
+ rc = hcall_return_busy_check(rc);
+ } while (rc == H_BUSY);
+
+ switch (rc) {
+ case H_SUCCESS:
+ return 0;
+ case H_PARAMETER:
+ pr_err("HCALL(%x): Invalid window ID %u\n",
+ H_MODIFY_VAS_WINDOW, win->winid);
+ return -EINVAL;
+ case H_P2:
+ pr_err("HCALL(%x): Window(%d): Invalid LPAR Process ID %u\n",
+ H_MODIFY_VAS_WINDOW, lpid, win->winid);
+ return -EINVAL;
+ case H_P3:
+ /* LPAR thread ID is deprecated on P10 */
+ pr_err("HCALL(%x): Invalid LPAR Thread ID for window(%u)\n",
+ H_MODIFY_VAS_WINDOW, win->winid);
+ return -EINVAL;
+ case H_STATE:
+ pr_err("HCALL(%x): Jobs in progress, Can't modify window(%u)\n",
+ H_MODIFY_VAS_WINDOW, win->winid);
+ return -EBUSY;
+ default:
+ pr_err("HCALL(%x): Unexpected error %lld for window(%u)\n",
+ H_MODIFY_VAS_WINDOW, rc, win->winid);
+ return -EIO;
+ }
+}
+
+/*
+ * This HCALL is used to determine the capabilities that pHyp provides.
+ * @hcall: H_QUERY_VAS_CAPABILITIES or H_QUERY_NX_CAPABILITIES
+ * @query_type: If 0 is passed, phyp returns the overall capabilities
+ * which provides all feature(s) that are available. Then
+ * query phyp to get the corresponding capabilities for
+ * the specific feature.
+ * Example: H_QUERY_VAS_CAPABILITIES provides VAS GZIP QoS
+ * and VAS GZIP Default capabilities.
+ * H_QUERY_NX_CAPABILITIES provides NX GZIP
+ * capabilities.
+ * @result: Return buffer to save capabilities.
+ */
+int plpar_vas_query_capabilities(const u64 hcall, u8 query_type,
+ u64 result)
+{
+ int64_t rc;
+
+ rc = plpar_hcall_norets(hcall, query_type, result);
+
+ switch (rc) {
+ case H_SUCCESS:
+ return 0;
+ case H_PARAMETER:
+ pr_err("HCALL(%llx): Invalid query type %u\n", hcall,
+ query_type);
+ return -EINVAL;
+ case H_PRIVILEGE:
+ pr_err("HCALL(%llx): Invalid result buffer 0x%llx\n",
+ hcall, result);
+ return -EACCES;
+ default:
+ pr_err("HCALL(%llx): Unexpected error %lld\n", hcall, rc);
+ return -EIO;
+ }
+}
--
2.18.2