When KVM panics, it hurridly restores the host context and parachutes
into the host's panic() code. This looks like it was copied from arm64,
the 32bit KVM panic code needs to restore the host's banked registers
too.
At some point panic() touches the physical timer/counter, this will
trap back to HYP. If we're lucky, we panic again.
Add a __timer_save_state() call to KVMs hyp_panic() path, this saves the
guest registers and disables the traps for the host.
Fixes: c36b6db5f3 ("ARM: KVM: Add panic handling code")
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Hardware debugging in guests is not intercepted currently, it means
that a malicious guest can bring down the entire machine by writing
to the debug registers.
This patch enable trapping of all debug registers, preventing the
guests to access the debug registers. This includes access to the
debug mode(DBGDSCR) in the guest world all the time which could
otherwise mess with the host state. Reads return 0 and writes are
ignored (RAZ_WI).
The result is the guest cannot detect any working hardware based debug
support. As debug exceptions are still routed to the guest normal
debug using software based breakpoints still works.
To support debugging using hardware registers we need to implement a
debug register aware world switch as well as special trapping for
registers that may affect the host state.
Cc: stable@vger.kernel.org
Signed-off-by: Zhichao Huang <zhichao.huang@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
This patch allows to build and use vgic-v3 in 32-bit mode.
Unfortunately, it can not be split in several steps without extra
stubs to keep patches independent and bisectable. For instance,
virt/kvm/arm/vgic/vgic-v3.c uses function from vgic-v3-sr.c, handling
access to GICv3 cpu interface from the guest requires vgic_v3.vgic_sre
to be already defined.
It is how support has been done:
* handle SGI requests from the guest
* report configured SRE on access to GICv3 cpu interface from the guest
* required vgic-v3 macros are provided via uapi.h
* static keys are used to select GIC backend
* to make vgic-v3 build KVM_ARM_VGIC_V3 guard is removed along with
the static inlines
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
The HCR.VA bit is used to signal an Abort to a guest, and has
the peculiar feature of getting cleared when the guest has taken
the abort (this is the only bit that behaves as such in this register).
This means that if we signal such an abort, we must leave it in
the guest context until it disappears from HCR, and at which point
it must be cleared from the context.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
When rewriting the assembly code to C code, it was useful to have
exported aliases or static functions so that we could keep the existing
common C code unmodified and at the same time rewrite arm64 from
assembly to C code, and later do the arm part.
Now when both are done, we really don't need this level of indirection
anymore, and it's time to save a few lines and brain cells.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
In order to be able to use the code located in virt/kvm/arm/hyp,
we need to make the global hyp.h file accessible from include/asm,
similar to what we did for arm64.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Now that the old code is long gone, we can remove all the weak
attributes, as there is only one version of the code.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Instead of spinning forever, let's "properly" handle any unexpected
exception ("properly" meaning "print a spat on the console and die").
This has proved useful quite a few times...
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
On guest exit, we must take care of populating our fault data
structure so that the host code can handle it. This includes
resolving the IPA for permission faults, which can result in
restarting the guest.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
The new world switch implementation is modeled after the arm64 one,
calling the various save/restore functions in turn, and having as
little state as possible.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
