From 5a44bb061d04b0306f2aa8add761d86d152b9377 Mon Sep 17 00:00:00 2001 From: Michael Mueller Date: Thu, 1 Aug 2024 14:31:09 +0200 Subject: KVM: s390: fix validity interception issue when gisa is switched off We might run into a SIE validity if gisa has been disabled either via using kernel parameter "kvm.use_gisa=0" or by setting the related sysfs attribute to N (echo N >/sys/module/kvm/parameters/use_gisa). The validity is caused by an invalid value in the SIE control block's gisa designation. That happens because we pass the uninitialized gisa origin to virt_to_phys() before writing it to the gisa designation. To fix this we return 0 in kvm_s390_get_gisa_desc() if the origin is 0. kvm_s390_get_gisa_desc() is used to determine which gisa designation to set in the SIE control block. A value of 0 in the gisa designation disables gisa usage. The issue surfaces in the host kernel with the following kernel message as soon a new kvm guest start is attemted. kvm: unhandled validity intercept 0x1011 WARNING: CPU: 0 PID: 781237 at arch/s390/kvm/intercept.c:101 kvm_handle_sie_intercept+0x42e/0x4d0 [kvm] Modules linked in: vhost_net tap tun xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT xt_tcpudp nft_compat x_tables nf_nat_tftp nf_conntrack_tftp vfio_pci_core irqbypass vhost_vsock vmw_vsock_virtio_transport_common vsock vhost vhost_iotlb kvm nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables sunrpc mlx5_ib ib_uverbs ib_core mlx5_core uvdevice s390_trng eadm_sch vfio_ccw zcrypt_cex4 mdev vfio_iommu_type1 vfio sch_fq_codel drm i2c_core loop drm_panel_orientation_quirks configfs nfnetlink lcs ctcm fsm dm_service_time ghash_s390 prng chacha_s390 libchacha aes_s390 des_s390 libdes sha3_512_s390 sha3_256_s390 sha512_s390 sha256_s390 sha1_s390 sha_common dm_mirror dm_region_hash dm_log zfcp scsi_transport_fc scsi_dh_rdac scsi_dh_emc scsi_dh_alua pkey zcrypt dm_multipath rng_core autofs4 [last unloaded: vfio_pci] CPU: 0 PID: 781237 Comm: CPU 0/KVM Not tainted 6.10.0-08682-gcad9f11498ea #6 Hardware name: IBM 3931 A01 701 (LPAR) Krnl PSW : 0704c00180000000 000003d93deb0122 (kvm_handle_sie_intercept+0x432/0x4d0 [kvm]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3 Krnl GPRS: 000003d900000027 000003d900000023 0000000000000028 000002cd00000000 000002d063a00900 00000359c6daf708 00000000000bebb5 0000000000001eff 000002cfd82e9000 000002cfd80bc000 0000000000001011 000003d93deda412 000003ff8962df98 000003d93de77ce0 000003d93deb011e 00000359c6daf960 Krnl Code: 000003d93deb0112: c020fffe7259 larl %r2,000003d93de7e5c4 000003d93deb0118: c0e53fa8beac brasl %r14,000003d9bd3c7e70 #000003d93deb011e: af000000 mc 0,0 >000003d93deb0122: a728ffea lhi %r2,-22 000003d93deb0126: a7f4fe24 brc 15,000003d93deafd6e 000003d93deb012a: 9101f0b0 tm 176(%r15),1 000003d93deb012e: a774fe48 brc 7,000003d93deafdbe 000003d93deb0132: 40a0f0ae sth %r10,174(%r15) Call Trace: [<000003d93deb0122>] kvm_handle_sie_intercept+0x432/0x4d0 [kvm] ([<000003d93deb011e>] kvm_handle_sie_intercept+0x42e/0x4d0 [kvm]) [<000003d93deacc10>] vcpu_post_run+0x1d0/0x3b0 [kvm] [<000003d93deaceda>] __vcpu_run+0xea/0x2d0 [kvm] [<000003d93dead9da>] kvm_arch_vcpu_ioctl_run+0x16a/0x430 [kvm] [<000003d93de93ee0>] kvm_vcpu_ioctl+0x190/0x7c0 [kvm] [<000003d9bd728b4e>] vfs_ioctl+0x2e/0x70 [<000003d9bd72a092>] __s390x_sys_ioctl+0xc2/0xd0 [<000003d9be0e9222>] __do_syscall+0x1f2/0x2e0 [<000003d9be0f9a90>] system_call+0x70/0x98 Last Breaking-Event-Address: [<000003d9bd3c7f58>] __warn_printk+0xe8/0xf0 Cc: stable@vger.kernel.org Reported-by: Christian Borntraeger Fixes: fe0ef0030463 ("KVM: s390: sort out physical vs virtual pointers usage") Signed-off-by: Michael Mueller Tested-by: Christian Borntraeger Reviewed-by: Janosch Frank Link: https://lore.kernel.org/r/20240801123109.2782155-1-mimu@linux.ibm.com Message-ID: <20240801123109.2782155-1-mimu@linux.ibm.com> Signed-off-by: Janosch Frank --- arch/s390/kvm/kvm-s390.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index bf8534218af3..e680c6bf0c9d 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -267,7 +267,12 @@ static inline unsigned long kvm_s390_get_gfn_end(struct kvm_memslots *slots) static inline u32 kvm_s390_get_gisa_desc(struct kvm *kvm) { - u32 gd = virt_to_phys(kvm->arch.gisa_int.origin); + u32 gd; + + if (!kvm->arch.gisa_int.origin) + return 0; + + gd = virt_to_phys(kvm->arch.gisa_int.origin); if (gd && sclp.has_gisaf) gd |= GISA_FORMAT1; -- cgit v1.2.3 From cff59d8631e1409ffdd22d9d717e15810181b32c Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Thu, 1 Aug 2024 13:25:48 +0200 Subject: s390/uv: Panic for set and remove shared access UVC errors The return value uv_set_shared() and uv_remove_shared() (which are wrappers around the share() function) is not always checked. The system integrity of a protected guest depends on the Share and Unshare UVCs being successful. This means that any caller that fails to check the return value will compromise the security of the protected guest. No code path that would lead to such violation of the security guarantees is currently exercised, since all the areas that are shared never get unshared during the lifetime of the system. This might change and become an issue in the future. The Share and Unshare UVCs can only fail in case of hypervisor misbehaviour (either a bug or malicious behaviour). In such cases there is no reasonable way forward, and the system needs to panic. This patch replaces the return at the end of the share() function with a panic, to guarantee system integrity. Fixes: 5abb9351dfd9 ("s390/uv: introduce guest side ultravisor code") Signed-off-by: Claudio Imbrenda Reviewed-by: Christian Borntraeger Reviewed-by: Steffen Eiden Reviewed-by: Janosch Frank Link: https://lore.kernel.org/r/20240801112548.85303-1-imbrenda@linux.ibm.com Message-ID: <20240801112548.85303-1-imbrenda@linux.ibm.com> [frankja@linux.ibm.com: Fixed up patch subject] Signed-off-by: Janosch Frank --- arch/s390/include/asm/uv.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h index 0b5f8f3e84f1..153d93468b77 100644 --- a/arch/s390/include/asm/uv.h +++ b/arch/s390/include/asm/uv.h @@ -441,7 +441,10 @@ static inline int share(unsigned long addr, u16 cmd) if (!uv_call(0, (u64)&uvcb)) return 0; - return -EINVAL; + pr_err("%s UVC failed (rc: 0x%x, rrc: 0x%x), possible hypervisor bug.\n", + uvcb.header.cmd == UVC_CMD_SET_SHARED_ACCESS ? "Share" : "Unshare", + uvcb.header.rc, uvcb.header.rrc); + panic("System security cannot be guaranteed unless the system panics now.\n"); } /* -- cgit v1.2.3