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KVM: arm64: Stop clobbering x0 for HVC_SOFT_RESTART

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commit b9e10d4a6c9f5cbe6369ce2c17ebc67d2e5a4be5 upstream.

HVC_SOFT_RESTART is given values for x0-2 that it should installed
before exiting to the new address so should not set x0 to stub HVC
success or failure code.

Fixes: af42f20480bf1 ("arm64: hyp-stub: Zero x0 on successful stub handling")
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200706095259.1338221-1-ascull@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andrew Scull 2020-07-06 10:52:59 +01:00 committed by Greg Kroah-Hartman
parent a20aa35b83
commit b956ec9afc
1 changed files with 7 additions and 4 deletions
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11
arch/arm64/kvm/hyp-init.S
View File

@ -136,11 +136,15 @@ ENTRY(__kvm_handle_stub_hvc)
1: cmp x0, #HVC_RESET_VECTORS
b.ne 1f
reset:
/*
* Reset kvm back to the hyp stub. Do not clobber x0-x4 in
* case we coming via HVC_SOFT_RESTART.
* Set the HVC_RESET_VECTORS return code before entering the common
* path so that we do not clobber x0-x2 in case we are coming via
* HVC_SOFT_RESTART.
*/
mov x0, xzr
reset:
/* Reset kvm back to the hyp stub. */
mrs x5, sctlr_el2
ldr x6, =SCTLR_ELx_FLAGS
bic x5, x5, x6 // Clear SCTL_M and etc
@ -151,7 +155,6 @@ reset:
/* Install stub vectors */
adr_l x5, __hyp_stub_vectors
msr vbar_el2, x5
mov x0, xzr
eret
1: /* Bad stub call */