blaster4385/linux-IllusionX/arch/x86/include, branch v6.12.10

x86/xen: remove hypercall page

2024-12-19T17:13:24Z

commit 7fa0da5373685e7ed249af3fa317ab1e1ba8b0a6 upstream. The hypercall page is no longer needed. It can be removed, as from the Xen perspective it is optional. But, from Linux's perspective, it removes naked RET instructions that escape the speculative protections that Call Depth Tracking and/or Untrain Ret are trying to achieve. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Reviewed-by: Andrew Cooper Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

x86/xen: use new hypercall functions instead of hypercall page

2024-12-19T17:13:23Z

commit b1c2cb86f4a7861480ad54bb9a58df3cbebf8e92 upstream. Call the Xen hypervisor via the new xen_hypercall_func static-call instead of the hypercall page. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Co-developed-by: Peter Zijlstra Co-developed-by: Josh Poimboeuf Signed-off-by: Greg Kroah-Hartman

x86/xen: add central hypercall functions

2024-12-19T17:13:23Z

commit b4845bb6383821a9516ce30af3a27dc873e37fd4 upstream. Add generic hypercall functions usable for all normal (i.e. not iret) hypercalls. Depending on the guest type and the processor vendor different functions need to be used due to the to be used instruction for entering the hypervisor: - PV guests need to use syscall - HVM/PVH guests on Intel need to use vmcall - HVM/PVH guests on AMD and Hygon need to use vmmcall As PVH guests need to issue hypercalls very early during boot, there is a 4th hypercall function needed for HVM/PVH which can be used on Intel and AMD processors. It will check the vendor type and then set the Intel or AMD specific function to use via static_call(). This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Co-developed-by: Peter Zijlstra Signed-off-by: Greg Kroah-Hartman

x86/static-call: provide a way to do very early static-call updates

2024-12-19T17:13:23Z

commit 0ef8047b737d7480a5d4c46d956e97c190f13050 upstream. Add static_call_update_early() for updating static-call targets in very early boot. This will be needed for support of Xen guest type specific hypercall functions. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Co-developed-by: Peter Zijlstra Co-developed-by: Josh Poimboeuf Signed-off-by: Greg Kroah-Hartman

x86: make get_cpu_vendor() accessible from Xen code

2024-12-19T17:13:23Z

commit efbcd61d9bebb771c836a3b8bfced8165633db7c upstream. In order to be able to differentiate between AMD and Intel based systems for very early hypercalls without having to rely on the Xen hypercall page, make get_cpu_vendor() non-static. Refactor early_cpu_init() for the same reason by splitting out the loop initializing cpu_devs() into an externally callable function. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

x86/mm: Add _PAGE_NOPTISHADOW bit to avoid updating userspace page tables

2024-12-14T19:03:33Z

commit d0ceea662d459726487030237689835fcc0483e5 upstream. The set_p4d() and set_pgd() functions (in 4-level or 5-level page table setups respectively) assume that the root page table is actually a 8KiB allocation, with the userspace root immediately after the kernel root page table (so that the former can enforce NX on on all the subordinate page tables, which are actually shared). However, users of the kernel_ident_mapping_init() code do not give it an 8KiB allocation for its PGD. Both swsusp_arch_resume() and acpi_mp_setup_reset() allocate only a single 4KiB page. The kexec code on x86_64 currently gets away with it purely by chance, because it allocates 8KiB for its "control code page" and then actually uses the first half for the PGD, then copies the actual trampoline code into the second half only after the identmap code has finished scribbling over it. Fix this by defining a _PAGE_NOPTISHADOW bit (which can use the same bit as _PAGE_SAVED_DIRTY since one is only for the PGD/P4D root and the other is exclusively for leaf PTEs.). This instructs __pti_set_user_pgtbl() not to write to the userspace 'shadow' PGD. Strictly, the _PAGE_NOPTISHADOW bit doesn't need to be written out to the actual page tables; since __pti_set_user_pgtbl() returns the value to be written to the kernel page table, it could be filtered out. But there seems to be no benefit to actually doing so. Suggested-by: Dave Hansen Signed-off-by: David Woodhouse Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/412c90a4df7aef077141d9f68d19cbe5602d6c6d.camel@infradead.org Cc: stable@kernel.org Cc: Linus Torvalds Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Rik van Riel Signed-off-by: Greg Kroah-Hartman

x86/mm: Carve out INVLPG inline asm for use by others

2024-12-05T13:02:57Z

commit f1d84b59cbb9547c243d93991acf187fdbe9fbe9 upstream. No functional changes. Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/ZyulbYuvrkshfsd2@antipodes Signed-off-by: Greg Kroah-Hartman

KVM: x86: switch hugepage recovery thread to vhost_task

2024-12-05T13:02:43Z

commit d96c77bd4eeba469bddbbb14323d2191684da82a upstream. kvm_vm_create_worker_thread() is meant to be used for kthreads that can consume significant amounts of CPU time on behalf of a VM or in response to how the VM behaves (for example how it accesses its memory). Therefore it wants to charge the CPU time consumed by that work to the VM's container. However, because of these threads, cgroups which have kvm instances inside never complete freezing. This can be trivially reproduced: root@test ~# mkdir /sys/fs/cgroup/test root@test ~# echo $$ > /sys/fs/cgroup/test/cgroup.procs root@test ~# qemu-system-x86_64 -nographic -enable-kvm and in another terminal: root@test ~# echo 1 > /sys/fs/cgroup/test/cgroup.freeze root@test ~# cat /sys/fs/cgroup/test/cgroup.events populated 1 frozen 0 The cgroup freezing happens in the signal delivery path but kvm_nx_huge_page_recovery_worker, while joining non-root cgroups, never calls into the signal delivery path and thus never gets frozen. Because the cgroup freezer determines whether a given cgroup is frozen by comparing the number of frozen threads to the total number of threads in the cgroup, the cgroup never becomes frozen and users waiting for the state transition may hang indefinitely. Since the worker kthread is tied to a user process, it's better if it behaves similarly to user tasks as much as possible, including being able to send SIGSTOP and SIGCONT. In fact, vhost_task is all that kvm_vm_create_worker_thread() wanted to be and more: not only it inherits the userspace process's cgroups, it has other niceties like being parented properly in the process tree. Use it instead of the homegrown alternative. Incidentally, the new code is also better behaved when you flip recovery back and forth to disabled and back to enabled. If your recovery period is 1 minute, it will run the next recovery after 1 minute independent of how many times you flipped the parameter. (Commit message based on emails from Tejun). Reported-by: Tejun Heo Reported-by: Luca Boccassi Acked-by: Tejun Heo Tested-by: Luca Boccassi Cc: stable@vger.kernel.org Reviewed-by: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

x86/tdx: Dynamically disable SEPT violations from causing #VEs

2024-12-05T13:02:11Z

[ Upstream commit f65aa0ad79fca4ace921da0701644f020129043d ] Memory access #VEs are hard for Linux to handle in contexts like the entry code or NMIs. But other OSes need them for functionality. There's a static (pre-guest-boot) way for a VMM to choose one or the other. But VMMs don't always know which OS they are booting, so they choose to deliver those #VEs so the "other" OSes will work. That, unfortunately has left us in the lurch and exposed to these hard-to-handle #VEs. The TDX module has introduced a new feature. Even if the static configuration is set to "send nasty #VEs", the kernel can dynamically request that they be disabled. Once they are disabled, access to private memory that is not in the Mapped state in the Secure-EPT (SEPT) will result in an exit to the VMM rather than injecting a #VE. Check if the feature is available and disable SEPT #VE if possible. If the TD is allowed to disable/enable SEPT #VEs, the ATTR_SEPT_VE_DISABLE attribute is no longer reliable. It reflects the initial state of the control for the TD, but it will not be updated if someone (e.g. bootloader) changes it before the kernel starts. Kernel must check TDCS_TD_CTLS bit to determine if SEPT #VEs are enabled or disabled. [ dhansen: remove 'return' at end of function ] Fixes: 373e715e31bf ("x86/tdx: Panic on bad configs that #VE on "private" memory access") Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Acked-by: Kai Huang Link: https://lore.kernel.org/all/20241104103803.195705-4-kirill.shutemov%40linux.intel.com Signed-off-by: Sasha Levin

x86/tdx: Introduce wrappers to read and write TD metadata

2024-12-05T13:02:11Z

[ Upstream commit 5081e8fadb809253c911b349b01d87c5b4e3fec5 ] The TDG_VM_WR TDCALL is used to ask the TDX module to change some TD-specific VM configuration. There is currently only one user in the kernel of this TDCALL leaf. More will be added shortly. Refactor to make way for more users of TDG_VM_WR who will need to modify other TD configuration values. Add a wrapper for the TDG_VM_RD TDCALL that requests TD-specific metadata from the TDX module. There are currently no users for TDG_VM_RD. Mark it as __maybe_unused until the first user appears. This is preparation for enumeration and enabling optional TD features. Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Reviewed-by: Kai Huang Reviewed-by: Kuppuswamy Sathyanarayanan Link: https://lore.kernel.org/all/20241104103803.195705-2-kirill.shutemov%40linux.intel.com Stable-dep-of: f65aa0ad79fc ("x86/tdx: Dynamically disable SEPT violations from causing #VEs") Signed-off-by: Sasha Levin