| From b9e10d4a6c9f5cbe6369ce2c17ebc67d2e5a4be5 Mon Sep 17 00:00:00 2001 |
| From: Andrew Scull <ascull@google.com> |
| Date: Mon, 6 Jul 2020 10:52:59 +0100 |
| Subject: KVM: arm64: Stop clobbering x0 for HVC_SOFT_RESTART |
| |
| From: Andrew Scull <ascull@google.com> |
| |
| 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> |
| |
| --- |
| arch/arm64/kvm/hyp-init.S | 11 +++++++---- |
| 1 file changed, 7 insertions(+), 4 deletions(-) |
| |
| --- a/arch/arm64/kvm/hyp-init.S |
| +++ b/arch/arm64/kvm/hyp-init.S |
| @@ -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 */ |
