From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- drivers/crypto/ccp/tee-dev.c | 399 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 399 insertions(+) create mode 100644 drivers/crypto/ccp/tee-dev.c (limited to 'drivers/crypto/ccp/tee-dev.c') diff --git a/drivers/crypto/ccp/tee-dev.c b/drivers/crypto/ccp/tee-dev.c new file mode 100644 index 000000000..3e3645980 --- /dev/null +++ b/drivers/crypto/ccp/tee-dev.c @@ -0,0 +1,399 @@ +// SPDX-License-Identifier: MIT +/* + * AMD Trusted Execution Environment (TEE) interface + * + * Author: Rijo Thomas + * Author: Devaraj Rangasamy + * + * Copyright (C) 2019,2021 Advanced Micro Devices, Inc. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "psp-dev.h" +#include "tee-dev.h" + +static bool psp_dead; + +static int tee_alloc_ring(struct psp_tee_device *tee, int ring_size) +{ + struct ring_buf_manager *rb_mgr = &tee->rb_mgr; + void *start_addr; + + if (!ring_size) + return -EINVAL; + + /* We need actual physical address instead of DMA address, since + * Trusted OS running on AMD Secure Processor will map this region + */ + start_addr = (void *)__get_free_pages(GFP_KERNEL, get_order(ring_size)); + if (!start_addr) + return -ENOMEM; + + memset(start_addr, 0x0, ring_size); + rb_mgr->ring_start = start_addr; + rb_mgr->ring_size = ring_size; + rb_mgr->ring_pa = __psp_pa(start_addr); + mutex_init(&rb_mgr->mutex); + + return 0; +} + +static void tee_free_ring(struct psp_tee_device *tee) +{ + struct ring_buf_manager *rb_mgr = &tee->rb_mgr; + + if (!rb_mgr->ring_start) + return; + + free_pages((unsigned long)rb_mgr->ring_start, + get_order(rb_mgr->ring_size)); + + rb_mgr->ring_start = NULL; + rb_mgr->ring_size = 0; + rb_mgr->ring_pa = 0; + mutex_destroy(&rb_mgr->mutex); +} + +static +struct tee_init_ring_cmd *tee_alloc_cmd_buffer(struct psp_tee_device *tee) +{ + struct tee_init_ring_cmd *cmd; + + cmd = kzalloc_obj(*cmd); + if (!cmd) + return NULL; + + cmd->hi_addr = upper_32_bits(tee->rb_mgr.ring_pa); + cmd->low_addr = lower_32_bits(tee->rb_mgr.ring_pa); + cmd->size = tee->rb_mgr.ring_size; + + dev_dbg(tee->dev, "tee: ring address: high = 0x%x low = 0x%x size = %u\n", + cmd->hi_addr, cmd->low_addr, cmd->size); + + return cmd; +} + +static inline void tee_free_cmd_buffer(struct tee_init_ring_cmd *cmd) +{ + kfree(cmd); +} + +static bool tee_send_destroy_cmd(struct psp_tee_device *tee) +{ + unsigned int reg; + int ret; + + ret = psp_mailbox_command(tee->psp, PSP_CMD_TEE_RING_DESTROY, NULL, + TEE_DEFAULT_CMD_TIMEOUT, ®); + if (ret) { + dev_err(tee->dev, "tee: ring destroy command timed out, disabling TEE support\n"); + psp_dead = true; + return false; + } + + if (FIELD_GET(PSP_CMDRESP_STS, reg)) { + dev_err(tee->dev, "tee: ring destroy command failed (%#010lx)\n", + FIELD_GET(PSP_CMDRESP_STS, reg)); + psp_dead = true; + return false; + } + + return true; +} + +static int tee_init_ring(struct psp_tee_device *tee) +{ + int ring_size = MAX_RING_BUFFER_ENTRIES * sizeof(struct tee_ring_cmd); + struct tee_init_ring_cmd *cmd; + bool retry = false; + unsigned int reg; + int ret; + + BUILD_BUG_ON(sizeof(struct tee_ring_cmd) != 1024); + + ret = tee_alloc_ring(tee, ring_size); + if (ret) { + dev_err(tee->dev, "tee: ring allocation failed %d\n", ret); + return ret; + } + + tee->rb_mgr.wptr = 0; + + cmd = tee_alloc_cmd_buffer(tee); + if (!cmd) { + tee_free_ring(tee); + return -ENOMEM; + } + + /* Send command buffer details to Trusted OS by writing to + * CPU-PSP message registers + */ +retry_init: + ret = psp_mailbox_command(tee->psp, PSP_CMD_TEE_RING_INIT, cmd, + TEE_DEFAULT_CMD_TIMEOUT, ®); + if (ret) { + dev_err(tee->dev, "tee: ring init command timed out, disabling TEE support\n"); + tee_free_ring(tee); + psp_dead = true; + goto free_buf; + } + + if (FIELD_GET(PSP_CMDRESP_STS, reg)) { + /* + * During the hibernate resume sequence driver may have gotten loaded + * but the ring not properly destroyed. If the ring doesn't work, try + * to destroy and re-init once. + */ + if (!retry && FIELD_GET(PSP_CMDRESP_STS, reg) == PSP_TEE_STS_RING_BUSY) { + dev_info(tee->dev, "tee: ring init command failed with busy status, retrying\n"); + if (tee_send_destroy_cmd(tee)) { + retry = true; + goto retry_init; + } + } + dev_err(tee->dev, "tee: ring init command failed (%#010lx)\n", + FIELD_GET(PSP_CMDRESP_STS, reg)); + tee_free_ring(tee); + psp_dead = true; + ret = -EIO; + } + +free_buf: + tee_free_cmd_buffer(cmd); + + return ret; +} + +static void tee_destroy_ring(struct psp_tee_device *tee) +{ + if (!tee->rb_mgr.ring_start) + return; + + if (psp_dead) + goto free_ring; + + tee_send_destroy_cmd(tee); + +free_ring: + tee_free_ring(tee); +} + +int tee_dev_init(struct psp_device *psp) +{ + struct device *dev = psp->dev; + struct psp_tee_device *tee; + int ret; + + ret = -ENOMEM; + tee = devm_kzalloc(dev, sizeof(*tee), GFP_KERNEL); + if (!tee) + goto e_err; + + psp->tee_data = tee; + + tee->dev = dev; + tee->psp = psp; + + tee->io_regs = psp->io_regs; + + tee->vdata = (struct tee_vdata *)psp->vdata->tee; + if (!tee->vdata) { + ret = -ENODEV; + dev_err(dev, "tee: missing driver data\n"); + goto e_err; + } + + ret = tee_init_ring(tee); + if (ret) { + dev_err(dev, "tee: failed to init ring buffer\n"); + goto e_err; + } + + dev_notice(dev, "tee enabled\n"); + + return 0; + +e_err: + psp->tee_data = NULL; + + dev_notice(dev, "tee initialization failed\n"); + + return ret; +} + +void tee_dev_destroy(struct psp_device *psp) +{ + struct psp_tee_device *tee = psp->tee_data; + + if (!tee) + return; + + tee_destroy_ring(tee); +} + +static int tee_submit_cmd(struct psp_tee_device *tee, enum tee_cmd_id cmd_id, + void *buf, size_t len, struct tee_ring_cmd **resp) +{ + struct tee_ring_cmd *cmd; + int nloop = 1000, ret = 0; + u32 rptr; + + *resp = NULL; + + mutex_lock(&tee->rb_mgr.mutex); + + /* Loop until empty entry found in ring buffer */ + do { + /* Get pointer to ring buffer command entry */ + cmd = (struct tee_ring_cmd *) + (tee->rb_mgr.ring_start + tee->rb_mgr.wptr); + + rptr = ioread32(tee->io_regs + tee->vdata->ring_rptr_reg); + + /* Check if ring buffer is full or command entry is waiting + * for response from TEE + */ + if (!(tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr || + cmd->flag == CMD_WAITING_FOR_RESPONSE)) + break; + + dev_dbg(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n", + rptr, tee->rb_mgr.wptr); + + /* Wait if ring buffer is full or TEE is processing data */ + mutex_unlock(&tee->rb_mgr.mutex); + schedule_timeout_interruptible(msecs_to_jiffies(10)); + mutex_lock(&tee->rb_mgr.mutex); + + } while (--nloop); + + if (!nloop && + (tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr || + cmd->flag == CMD_WAITING_FOR_RESPONSE)) { + dev_err(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u response flag %u\n", + rptr, tee->rb_mgr.wptr, cmd->flag); + ret = -EBUSY; + goto unlock; + } + + /* Do not submit command if PSP got disabled while processing any + * command in another thread + */ + if (psp_dead) { + ret = -EBUSY; + goto unlock; + } + + /* Write command data into ring buffer */ + cmd->cmd_id = cmd_id; + cmd->cmd_state = TEE_CMD_STATE_INIT; + memset(&cmd->buf[0], 0, sizeof(cmd->buf)); + memcpy(&cmd->buf[0], buf, len); + + /* Indicate driver is waiting for response */ + cmd->flag = CMD_WAITING_FOR_RESPONSE; + + /* Update local copy of write pointer */ + tee->rb_mgr.wptr += sizeof(struct tee_ring_cmd); + if (tee->rb_mgr.wptr >= tee->rb_mgr.ring_size) + tee->rb_mgr.wptr = 0; + + /* Trigger interrupt to Trusted OS */ + iowrite32(tee->rb_mgr.wptr, tee->io_regs + tee->vdata->ring_wptr_reg); + + /* The response is provided by Trusted OS in same + * location as submitted data entry within ring buffer. + */ + *resp = cmd; + +unlock: + mutex_unlock(&tee->rb_mgr.mutex); + + return ret; +} + +static int tee_wait_cmd_completion(struct psp_tee_device *tee, + struct tee_ring_cmd *resp, + unsigned int timeout) +{ + /* ~1ms sleep per loop => nloop = timeout * 1000 */ + int nloop = timeout * 1000; + + while (--nloop) { + if (resp->cmd_state == TEE_CMD_STATE_COMPLETED) + return 0; + + usleep_range(1000, 1100); + } + + dev_err(tee->dev, "tee: command 0x%x timed out, disabling PSP\n", + resp->cmd_id); + + psp_dead = true; + + return -ETIMEDOUT; +} + +int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len, + u32 *status) +{ + struct psp_device *psp = psp_get_master_device(); + struct psp_tee_device *tee; + struct tee_ring_cmd *resp; + int ret; + + if (!buf || !status || !len || len > sizeof(resp->buf)) + return -EINVAL; + + *status = 0; + + if (!psp || !psp->tee_data) + return -ENODEV; + + if (psp_dead) + return -EBUSY; + + tee = psp->tee_data; + + ret = tee_submit_cmd(tee, cmd_id, buf, len, &resp); + if (ret) + return ret; + + ret = tee_wait_cmd_completion(tee, resp, TEE_DEFAULT_RING_TIMEOUT); + if (ret) { + resp->flag = CMD_RESPONSE_TIMEDOUT; + return ret; + } + + memcpy(buf, &resp->buf[0], len); + *status = resp->status; + + resp->flag = CMD_RESPONSE_COPIED; + + return 0; +} +EXPORT_SYMBOL(psp_tee_process_cmd); + +int psp_check_tee_status(void) +{ + struct psp_device *psp = psp_get_master_device(); + + if (!psp || !psp->tee_data) + return -ENODEV; + + return 0; +} +EXPORT_SYMBOL(psp_check_tee_status); + +int tee_restore(struct psp_device *psp) +{ + return tee_init_ring(psp->tee_data); +} -- cgit v1.3.1