If EL1 generates an asynchronous abort and then traps into EL2
before the abort has been delivered, we may end-up with the
abort firing at the worse possible place: on the host.
In order to avoid this, it is necessary to take the abort at EL2,
by clearing the PSTATE.A bit. In order to survive this abort,
we do it at a point where we're in a known state with respect
to the world switch, and handle the resulting exception,
overloading the exit code in the process.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
SCTLR_EL2.SPAN bit controls what happens with the PSTATE.PAN bit on an
exception. However, this bit has no effect on the PSTATE.PAN when
HCR_EL2.E2H or HCR_EL2.TGE is unset. Thus when VHE is used and
exception taken from a guest PSTATE.PAN bit left unchanged and we
continue with a value guest has set.
To address that always reset PSTATE.PAN on entry from EL1.
Fixes: 1f364c8c48 ("arm64: VHE: Add support for running Linux in EL2 mode")
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: <stable@vger.kernel.org> # v4.6+
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
We are doing an unnecessary stack push/pop operation when restoring
the guest registers x0-x18 in __guest_enter(). This patch saves the
two instructions by using x18 as a base register. No need to store
the vcpu context pointer in stack because it is redundant, the same
information is available in tpidr_el2. The function __guest_exit()
calling convention is slightly modified, caller only pushes the regs
x0-x1 to stack instead of regs x0-x3.
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Now that we only have the "merged page tables" case to deal with,
there is a bunch of things we can simplify in the HYP code (both
at init and teardown time).
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
If memory is located above 1<<VA_BITS, kvm adds an extra level to its page
tables, merging the runtime tables and boot tables that contain the idmap.
This lets us avoid the trampoline dance during initialisation.
This also means there is no trampoline page mapped, so
__cpu_reset_hyp_mode() can't call __kvm_hyp_reset() in this page. The good
news is the idmap is still mapped, so we don't need the trampoline page.
The bad news is we can't call it directly as the idmap is above
HYP_PAGE_OFFSET, so its address is masked by kvm_call_hyp.
Add a function __extended_idmap_trampoline which will branch into
__kvm_hyp_reset in the idmap, change kvm_hyp_reset_entry() to return
this address if __kvm_cpu_uses_extended_idmap(). In this case
__kvm_hyp_reset() will still switch to the boot tables (which are the
merged tables that were already in use), and branch into the idmap (where
it already was).
This fixes boot failures on these systems, where we fail to execute the
missing trampoline page when tearing down kvm in init_subsystems():
[ 2.508922] kvm [1]: 8-bit VMID
[ 2.512057] kvm [1]: Hyp mode initialized successfully
[ 2.517242] kvm [1]: interrupt-controller@e1140000 IRQ13
[ 2.522622] kvm [1]: timer IRQ3
[ 2.525783] Kernel panic - not syncing: HYP panic:
[ 2.525783] PS:200003c9 PC:0000007ffffff820 ESR:86000005
[ 2.525783] FAR:0000007ffffff820 HPFAR:00000000003ffff0 PAR:0000000000000000
[ 2.525783] VCPU: (null)
[ 2.525783]
[ 2.547667] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.6.0-rc5+ #1
[ 2.555137] Hardware name: Default string Default string/Default string, BIOS ROD0084E 09/03/2015
[ 2.563994] Call trace:
[ 2.566432] [<ffffff80080888d0>] dump_backtrace+0x0/0x240
[ 2.571818] [<ffffff8008088b24>] show_stack+0x14/0x20
[ 2.576858] [<ffffff80083423ac>] dump_stack+0x94/0xb8
[ 2.581899] [<ffffff8008152130>] panic+0x10c/0x250
[ 2.586677] [<ffffff8008152024>] panic+0x0/0x250
[ 2.591281] SMP: stopping secondary CPUs
[ 3.649692] SMP: failed to stop secondary CPUs 0-2,4-7
[ 3.654818] Kernel Offset: disabled
[ 3.658293] Memory Limit: none
[ 3.661337] ---[ end Kernel panic - not syncing: HYP panic:
[ 3.661337] PS:200003c9 PC:0000007ffffff820 ESR:86000005
[ 3.661337] FAR:0000007ffffff820 HPFAR:00000000003ffff0 PAR:0000000000000000
[ 3.661337] VCPU: (null)
[ 3.661337]
Reported-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Despite the fact that a VHE enabled kernel runs at EL2, it uses
CPACR_EL1 to trap FPSIMD access. Add the required alternative
code to re-enable guest FPSIMD access when it has trapped to
EL2.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Having the system register numbers as #defines has been a pain
since day one, as the ordering is pretty fragile, and moving
things around leads to renumbering and epic conflict resolutions.
Now that we're mostly acessing the sysreg file in C, an enum is
a much better type to use, and we can clean things up a bit.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Implement the TLB handling as a direct translation of the assembly
code version.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Implement the fpsimd save restore, keeping the lazy part in
assembler (as returning to C would be overkill).
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Contrary to the previous patch, the guest entry is fairly different
from its assembly counterpart, mostly because it is only concerned
with saving/restoring the GP registers, and nothing else.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Marc Zyngier