Avoid getting xstate address of init_fpstate if fpstate contains the xstate component. Since XTILEDATA (bit 18) was turned off in xinit, when KVM calls __raw_xsave_addr(xinit, 18), it triggers a warning as follows.
__raw_xsave_addr() is an internal function that assume caller does the checking, ie., all function arguments should be checked before calling. So, instead of removing the WARNING, add checks in __copy_xstate_to_uabi_buf().
[ 168.814082] ------------[ cut here ]------------ [ 168.814083] WARNING: CPU: 35 PID: 15304 at arch/x86/kernel/fpu/xstate.c:934 __raw_xsave_addr+0xc8/0xe0 [ 168.814088] Modules linked in: kvm_intel dummy bridge stp llc cdc_ncm cdc_eem cdc_ether usbnet mii ehci_pci ehci_hcd vfat fat cdc_acm xhci_pci xhci_hcd idpf(O) [ 168.814100] CPU: 35 PID: 15304 Comm: amx_test Tainted: G S O 6.2.0-smp-DEV #6 [ 168.814103] RIP: 0010:__raw_xsave_addr+0xc8/0xe0 [ 168.814105] Code: 83 f9 40 72 b0 eb 10 48 63 ca 44 8b 04 8d 60 13 1e 82 eb 03 41 89 f8 44 89 c1 48 01 c8 48 83 c4 08 5d c3 cc 0f 0b 31 c0 eb f3 <0f> 0b 48 c7 c7 c7 28 11 82 e8 da 30 b0 00 31 c0 eb e1 66 0f 1f 44 [ 168.814106] RSP: 0018:ff110020ef79bc90 EFLAGS: 00010246 [ 168.814108] RAX: ffffffff821e0340 RBX: 0000000000000012 RCX: 0000000000000012 [ 168.814109] RDX: 0000000000000012 RSI: 80000000000206e7 RDI: 0000000000040000 [ 168.814110] RBP: ff110020ef79bc98 R08: 0000000000000a00 R09: 0000000000000012 [ 168.814112] R10: 0000000000000012 R11: 0000000000000004 R12: ffa00000089f2a40 [ 168.814113] R13: 0000001200000000 R14: 0000000000000012 R15: ff110020ef288b00 [ 168.814114] FS: 00007f1812761300(0000) GS:ff11003fff4c0000(0000) knlGS:0000000000000000 [ 168.814116] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 168.814117] CR2: 00007f1812555008 CR3: 0000002093a80002 CR4: 0000000000373ee0 [ 168.814118] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 168.814119] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 [ 168.814120] Call Trace: [ 168.814121] <TASK> [ 168.814122] __copy_xstate_to_uabi_buf+0x3cb/0x520 [ 168.814125] fpu_copy_guest_fpstate_to_uabi+0x29/0x50 [ 168.814127] kvm_arch_vcpu_ioctl+0x9f7/0xee0 [ 168.814130] ? __kmem_cache_free+0x16b/0x220 [ 168.814133] kvm_vcpu_ioctl+0x47c/0x5a0 [ 168.814136] __se_sys_ioctl+0x77/0xc0 [ 168.814138] __x64_sys_ioctl+0x1d/0x20 [ 168.814139] do_syscall_64+0x3d/0x80 [ 168.814142] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 168.814146] RIP: 0033:0x7f1812892c87 [ 168.814148] Code: 5d c3 cc 48 8b 05 39 1d 07 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 cc cc cc cc cc cc cc cc cc cc b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 09 1d 07 00 f7 d8 64 89 01 48 [ 168.814149] RSP: 002b:00007ffc4cebf538 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 168.814151] RAX: ffffffffffffffda RBX: 00007f1812761280 RCX: 00007f1812892c87 [ 168.814152] RDX: 00000000004dcda0 RSI: 000000009000aecf RDI: 0000000000000007 [ 168.814153] RBP: 0000000000002b00 R08: 00000000004d5010 R09: 0000000000002710 [ 168.814154] R10: 00007f1812906980 R11: 0000000000000246 R12: 00000000004d8110 [ 168.814155] R13: 0000000000000004 R14: 00000000004d78b0 R15: 0000000000000004 [ 168.814156] </TASK> [ 168.814157] ---[ end trace 0000000000000000 ]---
Fixes: e84ba47e313d ("x86/fpu: Hook up PKRU into ptrace()") Signed-off-by: Mingwei Zhang mizhang@google.com --- arch/x86/kernel/fpu/xstate.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 714166cc25f2..5cc1426c3800 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1063,6 +1063,7 @@ void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate, struct xregs_state *xsave = &fpstate->regs.xsave; struct xstate_header header; unsigned int zerofrom; + void *xsave_addr; u64 mask; int i;
@@ -1151,10 +1152,11 @@ void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate, pkru.pkru = pkru_val; membuf_write(&to, &pkru, sizeof(pkru)); } else { - copy_feature(header.xfeatures & BIT_ULL(i), &to, - __raw_xsave_addr(xsave, i), - __raw_xsave_addr(xinit, i), - xstate_sizes[i]); + xsave_addr = (header.xfeatures & BIT_ULL(i)) ? + __raw_xsave_addr(xsave, i) : + __raw_xsave_addr(xinit, i); + + membuf_write(&to, xsave_addr, xstate_sizes[i]); } /* * Keep track of the last copied state in the non-compacted