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Subject[PATCH v3 01/13] x86/fpu/xstate: Avoid getting xstate address of init_fpstate if fpstate contains the component
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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
--
2.39.2.637.g21b0678d19-goog
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