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Groups > linux.kernel > #1357489
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.14 02/19] KVM: PPC: Book3S HV: Sanitize special-purpose register values on guest exit |
| Date | 2016-03-14 19:10 +0100 |
| Message-ID | <rcF6k-7mS-57@gated-at.bofh.it> (permalink) |
| References | <rcF6i-7mS-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Mackerras <paulus@samba.org> commit ccec44563b18a0ce90e2d4f332784b3cb25c8e9c upstream. Thomas Huth discovered that a guest could cause a hard hang of a host CPU by setting the Instruction Authority Mask Register (IAMR) to a suitable value. It turns out that this is because when the code was added to context-switch the new special-purpose registers (SPRs) that were added in POWER8, we forgot to add code to ensure that they were restored to a sane value on guest exit. This adds code to set those registers where a bad value could compromise the execution of the host kernel to a suitable neutral value on guest exit. Fixes: b005255e12a3 Reported-by: Thomas Huth <thuth@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 14 ++++++++++++++ 1 file changed, 14 insertions(+) --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1148,6 +1148,20 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S) std r6, VCPU_ACOP(r9) stw r7, VCPU_GUEST_PID(r9) std r8, VCPU_WORT(r9) + /* + * Restore various registers to 0, where non-zero values + * set by the guest could disrupt the host. + */ + li r0, 0 + mtspr SPRN_IAMR, r0 + mtspr SPRN_CIABR, r0 + mtspr SPRN_DAWRX, r0 + mtspr SPRN_TCSCR, r0 + mtspr SPRN_WORT, r0 + /* Set MMCRS to 1<<31 to freeze and disable the SPMC counters */ + li r0, 1 + sldi r0, r0, 31 + mtspr SPRN_MMCRS, r0 8: /* Save and reset AMR and UAMOR before turning on the MMU */
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[PATCH 3.14 00/19] 3.14.65-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 18/19] modules: fix longstanding /proc/kallsyms vs module insertion race. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 14/19] efi: Make our variable validation list include the guid Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 12/19] efi: Use ucs2_as_utf8 in efivarfs instead of open coding a bad version Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 02/19] KVM: PPC: Book3S HV: Sanitize special-purpose register values on guest exit Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 05/19] ASoC: wm8958: Fix enum ctl accesses in a wrong type Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 08/19] mac80211: minstrel_ht: set default tx aggregation timeout to 0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 11/19] lib/ucs2_string: Add ucs2 -> utf8 helper functions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 03/19] tracing: Fix check for cpu online when event is disabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 07/19] mac80211: fix use of uninitialised values in RX aggregation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 06/19] wext: fix message delay/ordering Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 04/19] ASoC: wm8994: Fix enum ctl accesses in a wrong type Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 [PATCH 3.14 16/19] efi: Add pstore variables to the deletion whitelist Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100 Re: [PATCH 3.14 00/19] 3.14.65-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-15 00:20 +0100 Re: [PATCH 3.14 00/19] 3.14.65-stable review Guenter Roeck <linux@roeck-us.net> - 2016-03-15 03:40 +0100
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