Commit bfe766cf authored Dec 06, 2017 by Julien Thierry Committed by Christoffer Dall Dec 18, 2017

arm64: kvm: Prevent restoring stale PMSCR_EL1 for vcpu



When VHE is not present, KVM needs to save and restores PMSCR_EL1 when
possible. If SPE is used by the host, value of PMSCR_EL1 cannot be saved
for the guest.
If the host starts using SPE between two save+restore on the same vcpu,
restore will write the value of PMSCR_EL1 read during the first save.

Make sure __debug_save_spe_nvhe clears the value of the saved PMSCR_EL1
when the guest cannot use SPE.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

parent 50c4c4e2

arch/arm64/kvm/hyp/debug-sr.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -74,6 +74,9 @@ static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1)
		{
		u64 reg;

		/* Clear pmscr in case of early return */
		*pmscr_el1 = 0;

		/* SPE present on this CPU? */
		if (!cpuid_feature_extract_unsigned_field(read_sysreg(id_aa64dfr0_el1),
		ID_AA64DFR0_PMSVER_SHIFT))