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arm64: kvm: Prevent restoring stale PMSCR_EL1 for vcpu

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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>
This commit is contained in:
Julien Thierry 2017-12-06 17:09:49 +00:00 committed by Christoffer Dall
parent 50c4c4e268
commit bfe766cf65
1 changed files with 3 additions and 0 deletions
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3
arch/arm64/kvm/hyp/debug-sr.c
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@ -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))