From: Vasant Karasulli <vkarasulli(a)suse.de>
Hi,
here are changes to enable kexec/kdump in SEV-ES guests. The biggest
problem for supporting kexec/kdump under SEV-ES is to find a way to
hand the non-boot CPUs (APs) from one kernel to another.
Without SEV-ES the first kernel parks the CPUs in a HLT loop until
they get reset by the kexec'ed kernel via an INIT-SIPI-SIPI sequence.
For virtual machines the CPU reset is emulated by the hypervisor,
which sets the vCPU registers back to reset state.
This does not work under SEV-ES, because the hypervisor has no access
to the vCPU registers and can't make modifications to them. So an
SEV-ES guest needs to reset the vCPU itself and park it using the
AP-reset-hold protocol. Upon wakeup the guest needs to jump to
real-mode and to the reset-vector configured in the AP-Jump-Table.
The code to do this is the main part of this patch-set. It works by
placing code on the AP Jump-Table page itself to park the vCPU and for
jumping to the reset vector upon wakeup. The code on the AP Jump Table
runs in 16-bit protected mode with segment base set to the beginning
of the page. The AP Jump-Table is usually not within the first 1MB of
memory, so the code can't run in real-mode.
The AP Jump-Table is the best place to put the parking code, because
the memory is owned, but read-only by the firmware and writeable by
the OS. Only the first 4 bytes are used for the reset-vector, leaving
the rest of the page for code/data/stack to park a vCPU. The code
can't be in kernel memory because by the time the vCPU wakes up the
memory will be owned by the new kernel, which might have overwritten it
already.
The other patches add initial GHCB Version 2 protocol support, because
kexec/kdump need the MSR-based (without a GHCB) AP-reset-hold VMGEXIT,
which is a GHCB protocol version 2 feature.
The kexec'ed kernel is also entered via the decompressor and needs
MMIO support there, so this patch-set also adds MMIO #VC support to
the decompressor and support for handling CLFLUSH instructions.
Finally there is also code to disable kexec/kdump support at runtime
when the environment does not support it (e.g. no GHCB protocol
version 2 support or AP Jump Table over 4GB).
The diffstat looks big, but most of it is moving code for MMIO #VC
support around to make it available to the decompressor.
The previous version of this patch-set can be found here:
https://lore.kernel.org/lkml/20220127101044.13803-1-joro@8bytes.org/
Please review.
Thanks,
Vasant
Changes v3->v4:
- Rebased to v6.8 kernel
- Applied review comments by Sean Christopherson
- Combined sev_es_setup_ap_jump_table() and sev_setup_ap_jump_table()
into a single function which makes caching jump table address
unnecessary
- annotated struct sev_ap_jump_table_header with __packed attribute
- added code to set up real mode data segment at boot time instead of
hardcoding the value.
Changes v2->v3:
- Rebased to v5.17-rc1
- Applied most review comments by Boris
- Use the name 'AP jump table' consistently
- Make kexec-disabling for unsupported guests x86-specific
- Cleanup and consolidate patches to detect GHCB v2 protocol
support
Joerg Roedel (9):
x86/kexec/64: Disable kexec when SEV-ES is active
x86/sev: Save and print negotiated GHCB protocol version
x86/sev: Set GHCB data structure version
x86/sev: Setup code to park APs in the AP Jump Table
x86/sev: Park APs on AP Jump Table with GHCB protocol version 2
x86/sev: Use AP Jump Table blob to stop CPU
x86/sev: Add MMIO handling support to boot/compressed/ code
x86/sev: Handle CLFLUSH MMIO events
x86/kexec/64: Support kexec under SEV-ES with AP Jump Table Blob
arch/x86/boot/compressed/sev.c | 45 +-
arch/x86/include/asm/insn-eval.h | 1 +
arch/x86/include/asm/realmode.h | 5 +
arch/x86/include/asm/sev-ap-jumptable.h | 30 +
arch/x86/include/asm/sev.h | 7 +
arch/x86/kernel/machine_kexec_64.c | 12 +
arch/x86/kernel/process.c | 8 +
arch/x86/kernel/sev-shared.c | 234 +++++-
arch/x86/kernel/sev.c | 372 +++++-----
arch/x86/lib/insn-eval-shared.c | 912 ++++++++++++++++++++++++
arch/x86/lib/insn-eval.c | 911 +----------------------
arch/x86/realmode/Makefile | 9 +-
arch/x86/realmode/rm/Makefile | 11 +-
arch/x86/realmode/rm/header.S | 3 +
arch/x86/realmode/rm/sev.S | 85 +++
arch/x86/realmode/rmpiggy.S | 6 +
arch/x86/realmode/sev/Makefile | 33 +
arch/x86/realmode/sev/ap_jump_table.S | 131 ++++
arch/x86/realmode/sev/ap_jump_table.lds | 24 +
19 files changed, 1695 insertions(+), 1144 deletions(-)
create mode 100644 arch/x86/include/asm/sev-ap-jumptable.h
create mode 100644 arch/x86/lib/insn-eval-shared.c
create mode 100644 arch/x86/realmode/rm/sev.S
create mode 100644 arch/x86/realmode/sev/Makefile
create mode 100644 arch/x86/realmode/sev/ap_jump_table.S
create mode 100644 arch/x86/realmode/sev/ap_jump_table.lds
base-commit: e8f897f4afef0031fe618a8e94127a0934896aba
--
2.34.1
This is the backport of recently upstreamed series that moves VERW
execution to a later point in exit-to-user path. This is needed because
in some cases it may be possible for data accessed after VERW executions
may end into MDS affected CPU buffers. Moving VERW closer to ring
transition reduces the attack surface.
- The series includes a dependency commit f87bc8dc7a7c ("x86/asm: Add
_ASM_RIP() macro for x86-64 (%rip) suffix").
- Patch 2 includes a change that adds runtime patching for jmp (instead
of verw in original series) due to lack of rip-relative relocation
support in kernels <v6.5.
- Fixed warning:
arch/x86/entry/entry.o: warning: objtool: mds_verw_sel+0x0: unreachable instruction.
- Resolved merge conflicts in:
swapgs_restore_regs_and_return_to_usermode in entry_64.S.
__vmx_vcpu_run in vmenter.S.
vmx_update_fb_clear_dis in vmx.c.
- Boot tested with KASLR and KPTI enabled.
- Verified VERW being executed with mitigation ON, and not being
executed with mitigation turned OFF.
To: stable(a)vger.kernel.org
Signed-off-by: Pawan Gupta <pawan.kumar.gupta(a)linux.intel.com>
---
H. Peter Anvin (Intel) (1):
x86/asm: Add _ASM_RIP() macro for x86-64 (%rip) suffix
Pawan Gupta (5):
x86/bugs: Add asm helpers for executing VERW
x86/entry_64: Add VERW just before userspace transition
x86/entry_32: Add VERW just before userspace transition
x86/bugs: Use ALTERNATIVE() instead of mds_user_clear static key
KVM/VMX: Move VERW closer to VMentry for MDS mitigation
Sean Christopherson (1):
KVM/VMX: Use BT+JNC, i.e. EFLAGS.CF to select VMRESUME vs. VMLAUNCH
Documentation/x86/mds.rst | 38 +++++++++++++++++++++++++-----------
arch/x86/entry/entry.S | 23 ++++++++++++++++++++++
arch/x86/entry/entry_32.S | 3 +++
arch/x86/entry/entry_64.S | 11 +++++++++++
arch/x86/entry/entry_64_compat.S | 1 +
arch/x86/include/asm/asm.h | 5 +++++
arch/x86/include/asm/cpufeatures.h | 2 +-
arch/x86/include/asm/entry-common.h | 1 -
arch/x86/include/asm/nospec-branch.h | 27 +++++++++++++------------
arch/x86/kernel/cpu/bugs.c | 15 ++++++--------
arch/x86/kernel/nmi.c | 3 ---
arch/x86/kvm/vmx/run_flags.h | 7 +++++--
arch/x86/kvm/vmx/vmenter.S | 9 ++++++---
arch/x86/kvm/vmx/vmx.c | 12 ++++++++----
14 files changed, 111 insertions(+), 46 deletions(-)
---
base-commit: 80efc6265290d34b75921bf7294e0d9c5a8749dc
change-id: 20240304-delay-verw-backport-5-15-y-e16f07fbb71e
Best regards,
--
Thanks,
Pawan
From: Filipe Manana <fdmanana(a)suse.com>
[ Upstream commit e06cc89475eddc1f3a7a4d471524256152c68166 ]
At space_info.c we have several places where we access the ->reserved
field of a block reserve without taking the block reserve's spinlock
first, which makes KCSAN warn about a data race since that field is
always updated while holding the spinlock.
The reports from KCSAN are like the following:
[117.193526] BUG: KCSAN: data-race in btrfs_block_rsv_release [btrfs] / need_preemptive_reclaim [btrfs]
[117.195148] read to 0x000000017f587190 of 8 bytes by task 6303 on cpu 3:
[117.195172] need_preemptive_reclaim+0x222/0x2f0 [btrfs]
[117.195992] __reserve_bytes+0xbb0/0xdc8 [btrfs]
[117.196807] btrfs_reserve_metadata_bytes+0x4c/0x120 [btrfs]
[117.197620] btrfs_block_rsv_add+0x78/0xa8 [btrfs]
[117.198434] btrfs_delayed_update_inode+0x154/0x368 [btrfs]
[117.199300] btrfs_update_inode+0x108/0x1c8 [btrfs]
[117.200122] btrfs_dirty_inode+0xb4/0x140 [btrfs]
[117.200937] btrfs_update_time+0x8c/0xb0 [btrfs]
[117.201754] touch_atime+0x16c/0x1e0
[117.201789] filemap_read+0x674/0x728
[117.201823] btrfs_file_read_iter+0xf8/0x410 [btrfs]
[117.202653] vfs_read+0x2b6/0x498
[117.203454] ksys_read+0xa2/0x150
[117.203473] __s390x_sys_read+0x68/0x88
[117.203495] do_syscall+0x1c6/0x210
[117.203517] __do_syscall+0xc8/0xf0
[117.203539] system_call+0x70/0x98
[117.203579] write to 0x000000017f587190 of 8 bytes by task 11 on cpu 0:
[117.203604] btrfs_block_rsv_release+0x2e8/0x578 [btrfs]
[117.204432] btrfs_delayed_inode_release_metadata+0x7c/0x1d0 [btrfs]
[117.205259] __btrfs_update_delayed_inode+0x37c/0x5e0 [btrfs]
[117.206093] btrfs_async_run_delayed_root+0x356/0x498 [btrfs]
[117.206917] btrfs_work_helper+0x160/0x7a0 [btrfs]
[117.207738] process_one_work+0x3b6/0x838
[117.207768] worker_thread+0x75e/0xb10
[117.207797] kthread+0x21a/0x230
[117.207830] __ret_from_fork+0x6c/0xb8
[117.207861] ret_from_fork+0xa/0x30
So add a helper to get the reserved amount of a block reserve while
holding the lock. The value may be not be up to date anymore when used by
need_preemptive_reclaim() and btrfs_preempt_reclaim_metadata_space(), but
that's ok since the worst it can do is cause more reclaim work do be done
sooner rather than later. Reading the field while holding the lock instead
of using the data_race() annotation is used in order to prevent load
tearing.
Signed-off-by: Filipe Manana <fdmanana(a)suse.com>
Reviewed-by: David Sterba <dsterba(a)suse.com>
Signed-off-by: David Sterba <dsterba(a)suse.com>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
fs/btrfs/block-rsv.h | 16 ++++++++++++++++
fs/btrfs/space-info.c | 26 +++++++++++++-------------
2 files changed, 29 insertions(+), 13 deletions(-)
diff --git a/fs/btrfs/block-rsv.h b/fs/btrfs/block-rsv.h
index 578c3497a455c..cda79d3e0c263 100644
--- a/fs/btrfs/block-rsv.h
+++ b/fs/btrfs/block-rsv.h
@@ -101,4 +101,20 @@ static inline bool btrfs_block_rsv_full(const struct btrfs_block_rsv *rsv)
return data_race(rsv->full);
}
+/*
+ * Get the reserved mount of a block reserve in a context where getting a stale
+ * value is acceptable, instead of accessing it directly and trigger data race
+ * warning from KCSAN.
+ */
+static inline u64 btrfs_block_rsv_reserved(struct btrfs_block_rsv *rsv)
+{
+ u64 ret;
+
+ spin_lock(&rsv->lock);
+ ret = rsv->reserved;
+ spin_unlock(&rsv->lock);
+
+ return ret;
+}
+
#endif /* BTRFS_BLOCK_RSV_H */
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 2635fb4bffa06..8b75f436a9a3c 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -847,7 +847,7 @@ btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
static bool need_preemptive_reclaim(struct btrfs_fs_info *fs_info,
struct btrfs_space_info *space_info)
{
- u64 global_rsv_size = fs_info->global_block_rsv.reserved;
+ const u64 global_rsv_size = btrfs_block_rsv_reserved(&fs_info->global_block_rsv);
u64 ordered, delalloc;
u64 total = writable_total_bytes(fs_info, space_info);
u64 thresh;
@@ -948,8 +948,8 @@ static bool need_preemptive_reclaim(struct btrfs_fs_info *fs_info,
ordered = percpu_counter_read_positive(&fs_info->ordered_bytes) >> 1;
delalloc = percpu_counter_read_positive(&fs_info->delalloc_bytes);
if (ordered >= delalloc)
- used += fs_info->delayed_refs_rsv.reserved +
- fs_info->delayed_block_rsv.reserved;
+ used += btrfs_block_rsv_reserved(&fs_info->delayed_refs_rsv) +
+ btrfs_block_rsv_reserved(&fs_info->delayed_block_rsv);
else
used += space_info->bytes_may_use - global_rsv_size;
@@ -1164,7 +1164,7 @@ static void btrfs_preempt_reclaim_metadata_space(struct work_struct *work)
enum btrfs_flush_state flush;
u64 delalloc_size = 0;
u64 to_reclaim, block_rsv_size;
- u64 global_rsv_size = global_rsv->reserved;
+ const u64 global_rsv_size = btrfs_block_rsv_reserved(global_rsv);
loops++;
@@ -1176,9 +1176,9 @@ static void btrfs_preempt_reclaim_metadata_space(struct work_struct *work)
* assume it's tied up in delalloc reservations.
*/
block_rsv_size = global_rsv_size +
- delayed_block_rsv->reserved +
- delayed_refs_rsv->reserved +
- trans_rsv->reserved;
+ btrfs_block_rsv_reserved(delayed_block_rsv) +
+ btrfs_block_rsv_reserved(delayed_refs_rsv) +
+ btrfs_block_rsv_reserved(trans_rsv);
if (block_rsv_size < space_info->bytes_may_use)
delalloc_size = space_info->bytes_may_use - block_rsv_size;
@@ -1198,16 +1198,16 @@ static void btrfs_preempt_reclaim_metadata_space(struct work_struct *work)
to_reclaim = delalloc_size;
flush = FLUSH_DELALLOC;
} else if (space_info->bytes_pinned >
- (delayed_block_rsv->reserved +
- delayed_refs_rsv->reserved)) {
+ (btrfs_block_rsv_reserved(delayed_block_rsv) +
+ btrfs_block_rsv_reserved(delayed_refs_rsv))) {
to_reclaim = space_info->bytes_pinned;
flush = COMMIT_TRANS;
- } else if (delayed_block_rsv->reserved >
- delayed_refs_rsv->reserved) {
- to_reclaim = delayed_block_rsv->reserved;
+ } else if (btrfs_block_rsv_reserved(delayed_block_rsv) >
+ btrfs_block_rsv_reserved(delayed_refs_rsv)) {
+ to_reclaim = btrfs_block_rsv_reserved(delayed_block_rsv);
flush = FLUSH_DELAYED_ITEMS_NR;
} else {
- to_reclaim = delayed_refs_rsv->reserved;
+ to_reclaim = btrfs_block_rsv_reserved(delayed_refs_rsv);
flush = FLUSH_DELAYED_REFS_NR;
}
--
2.43.0
From: Ranjan Kumar <ranjan.kumar(a)broadcom.com>
[ Upstream commit ee0017c3ed8a8abfa4d40e42f908fb38c31e7515 ]
If the driver detects that the controller is not ready before sending the
first IOC facts command, it will wait for a maximum of 10 seconds for it to
become ready. However, even if the controller becomes ready within 10
seconds, the driver will still issue a diagnostic reset.
Modify the driver to avoid sending a diag reset if the controller becomes
ready within the 10-second wait time.
Signed-off-by: Ranjan Kumar <ranjan.kumar(a)broadcom.com>
Link: https://lore.kernel.org/r/20240221071724.14986-1-ranjan.kumar@broadcom.com
Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
drivers/scsi/mpt3sas/mpt3sas_base.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 447ac667f4b2b..7588c2c11a879 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -5584,7 +5584,9 @@ _base_wait_for_iocstate(struct MPT3SAS_ADAPTER *ioc, int timeout)
return -EFAULT;
}
- issue_diag_reset:
+ return 0;
+
+issue_diag_reset:
rc = _base_diag_reset(ioc);
return rc;
}
--
2.43.0