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/scsi/scsi_debugfs.c | 75 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 drivers/scsi/scsi_debugfs.c (limited to 'drivers/scsi/scsi_debugfs.c') diff --git a/drivers/scsi/scsi_debugfs.c b/drivers/scsi/scsi_debugfs.c new file mode 100644 index 000000000..eb52e39f3 --- /dev/null +++ b/drivers/scsi/scsi_debugfs.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include "scsi_debugfs.h" + +#define SCSI_CMD_FLAG_NAME(name)[const_ilog2(SCMD_##name)] = #name +static const char *const scsi_cmd_flags[] = { + SCSI_CMD_FLAG_NAME(TAGGED), + SCSI_CMD_FLAG_NAME(INITIALIZED), + SCSI_CMD_FLAG_NAME(LAST), +}; +#undef SCSI_CMD_FLAG_NAME + +static int scsi_flags_show(struct seq_file *m, const unsigned long flags, + const char *const *flag_name, int flag_name_count) +{ + bool sep = false; + int i; + + for_each_set_bit(i, &flags, BITS_PER_LONG) { + if (sep) + seq_puts(m, "|"); + sep = true; + if (i < flag_name_count && flag_name[i]) + seq_puts(m, flag_name[i]); + else + seq_printf(m, "%d", i); + } + return 0; +} + +static const char *scsi_cmd_list_info(struct scsi_cmnd *cmd) +{ + struct Scsi_Host *shost = cmd->device->host; + struct scsi_cmnd *cmd2; + + guard(spinlock_irq)(shost->host_lock); + + list_for_each_entry(cmd2, &shost->eh_abort_list, eh_entry) + if (cmd == cmd2) + return "on eh_abort_list"; + + list_for_each_entry(cmd2, &shost->eh_cmd_q, eh_entry) + if (cmd == cmd2) + return "on eh_cmd_q"; + + return NULL; +} + +void scsi_show_rq(struct seq_file *m, struct request *rq) +{ + struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); + int alloc_ms = jiffies_to_msecs(jiffies - cmd->jiffies_at_alloc); + int timeout_ms = jiffies_to_msecs(rq->timeout); + char buf[80] = "(?)"; + + if (cmd->flags & SCMD_INITIALIZED) { + const char *list_info = scsi_cmd_list_info(cmd); + + __scsi_format_command(buf, sizeof(buf), cmd->cmnd, cmd->cmd_len); + seq_printf(m, ", .cmd=%s, .retries=%d, .allowed=%d, .result = %#x%s%s", + buf, cmd->retries, cmd->allowed, cmd->result, + list_info ? ", " : "", list_info ? : ""); + seq_printf(m, ", .timeout=%d.%03d, allocated %d.%03d s ago", + timeout_ms / 1000, timeout_ms % 1000, + alloc_ms / 1000, alloc_ms % 1000); + } + seq_printf(m, ", .flags="); + scsi_flags_show(m, cmd->flags, scsi_cmd_flags, + ARRAY_SIZE(scsi_cmd_flags)); +} -- cgit v1.3.1