[PATCH 4.14 57/74] arm64: kvm: Prevent restoring stale PMSCR_EL1 for vcpu

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

--

From: Julien Thierry 

commit bfe766cf65fb65e68c4764f76158718560bdcee5 upstream.

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 
Cc: Christoffer Dall 
Cc: Marc Zyngier 
Cc: Catalin Marinas 
Reviewed-by: Will Deacon 
Reviewed-by: Christoffer Dall 
Signed-off-by: Christoffer Dall 
Signed-off-by: Greg Kroah-Hartman 

---
 arch/arm64/kvm/hyp/debug-sr.c |3 +++
 1 file changed, 3 insertions(+)

--- a/arch/arm64/kvm/hyp/debug-sr.c
+++ b/arch/arm64/kvm/hyp/debug-sr.c
@@ -84,6 +84,9 @@ static void __hyp_text __debug_save_spe_
 {
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))

[PATCH 4.14 57/74] arm64: kvm: Prevent restoring stale PMSCR_EL1 for vcpu

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

--

From: Julien Thierry 

commit bfe766cf65fb65e68c4764f76158718560bdcee5 upstream.

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 
Cc: Christoffer Dall 
Cc: Marc Zyngier 
Cc: Catalin Marinas 
Reviewed-by: Will Deacon 
Reviewed-by: Christoffer Dall 
Signed-off-by: Christoffer Dall 
Signed-off-by: Greg Kroah-Hartman 

---
 arch/arm64/kvm/hyp/debug-sr.c |3 +++
 1 file changed, 3 insertions(+)

--- a/arch/arm64/kvm/hyp/debug-sr.c
+++ b/arch/arm64/kvm/hyp/debug-sr.c
@@ -84,6 +84,9 @@ static void __hyp_text __debug_save_spe_
 {
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))