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authorMarc Zyngier <marc.zyngier@arm.com>2019-01-19 15:29:54 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2019-02-19 21:05:35 +0000
commit32f139551954512bfdf9d558341af453bb8b12b4 (patch)
treed7fc878ae67aab3ab2300b3ca72e51f03ff3482b
parentd18232ea8a9480606c53e91d7e2d062c3c151815 (diff)
downloadlinux-32f139551954512bfdf9d558341af453bb8b12b4.tar.bz2
arm/arm64: KVM: Statically configure the host's view of MPIDR
We currently eagerly save/restore MPIDR. It turns out to be slightly pointless: - On the host, this value is known as soon as we're scheduled on a physical CPU - In the guest, this value cannot change, as it is set by KVM (and this is a read-only register) The result of the above is that we can perfectly avoid the eager saving of MPIDR_EL1, and only keep the restore. We just have to setup the host contexts appropriately at boot time. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
-rw-r--r--arch/arm/include/asm/kvm_host.h8
-rw-r--r--arch/arm/kvm/hyp/cp15-sr.c1
-rw-r--r--arch/arm64/include/asm/kvm_host.h8
-rw-r--r--arch/arm64/kvm/hyp/sysreg-sr.c1
-rw-r--r--virt/kvm/arm/arm.c1
5 files changed, 17 insertions, 2 deletions
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 4b6193f2f0f6..43e343e00fb8 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -26,6 +26,7 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_mmio.h>
#include <asm/fpstate.h>
+#include <asm/smp_plat.h>
#include <kvm/arm_arch_timer.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -147,6 +148,13 @@ struct kvm_cpu_context {
typedef struct kvm_cpu_context kvm_cpu_context_t;
+static inline void kvm_init_host_cpu_context(kvm_cpu_context_t *cpu_ctxt,
+ int cpu)
+{
+ /* The host's MPIDR is immutable, so let's set it up at boot time */
+ cpu_ctxt->cp15[c0_MPIDR] = cpu_logical_map(cpu);
+}
+
struct kvm_vcpu_arch {
struct kvm_cpu_context ctxt;
diff --git a/arch/arm/kvm/hyp/cp15-sr.c b/arch/arm/kvm/hyp/cp15-sr.c
index c4782812714c..8bf895ec6e04 100644
--- a/arch/arm/kvm/hyp/cp15-sr.c
+++ b/arch/arm/kvm/hyp/cp15-sr.c
@@ -27,7 +27,6 @@ static u64 *cp15_64(struct kvm_cpu_context *ctxt, int idx)
void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
{
- ctxt->cp15[c0_MPIDR] = read_sysreg(VMPIDR);
ctxt->cp15[c0_CSSELR] = read_sysreg(CSSELR);
ctxt->cp15[c1_SCTLR] = read_sysreg(SCTLR);
ctxt->cp15[c1_CPACR] = read_sysreg(CPACR);
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 8b7702bdb219..f497bb31031f 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -30,6 +30,7 @@
#include <asm/kvm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_mmio.h>
+#include <asm/smp_plat.h>
#include <asm/thread_info.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -418,6 +419,13 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
DECLARE_PER_CPU(kvm_cpu_context_t, kvm_host_cpu_state);
+static inline void kvm_init_host_cpu_context(kvm_cpu_context_t *cpu_ctxt,
+ int cpu)
+{
+ /* The host's MPIDR is immutable, so let's set it up at boot time */
+ cpu_ctxt->sys_regs[MPIDR_EL1] = cpu_logical_map(cpu);
+}
+
void __kvm_enable_ssbs(void);
static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 68d6f7c3b237..2498f86defcb 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -52,7 +52,6 @@ static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
{
- ctxt->sys_regs[MPIDR_EL1] = read_sysreg(vmpidr_el2);
ctxt->sys_regs[CSSELR_EL1] = read_sysreg(csselr_el1);
ctxt->sys_regs[SCTLR_EL1] = read_sysreg_el1(sctlr);
ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 4d55f98f97f7..3dd240ea9e76 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -1561,6 +1561,7 @@ static int init_hyp_mode(void)
kvm_cpu_context_t *cpu_ctxt;
cpu_ctxt = per_cpu_ptr(&kvm_host_cpu_state, cpu);
+ kvm_init_host_cpu_context(cpu_ctxt, cpu);
err = create_hyp_mappings(cpu_ctxt, cpu_ctxt + 1, PAGE_HYP);
if (err) {