From: Yang Weijiang <weijiang.yang@intel.com>
To: seanjc@google.com, pbonzini@redhat.com, peterz@infradead.org,
john.allen@amd.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: rick.p.edgecombe@intel.com, chao.gao@intel.com,
binbin.wu@linux.intel.com, weijiang.yang@intel.com
Subject: [PATCH v4 10/20] KVM:x86: Make guest supervisor states as non-XSAVE managed
Date: Thu, 20 Jul 2023 23:03:42 -0400 [thread overview]
Message-ID: <20230721030352.72414-11-weijiang.yang@intel.com> (raw)
In-Reply-To: <20230721030352.72414-1-weijiang.yang@intel.com>
Save and reload guest CET supervisor states, i.e.,PL{0,1,2}_SSP,
when vCPU context is being swapped before and after userspace
<->kernel entry, also do the same operation when vCPU is sched-in
or sched-out.
Enabling CET supervisor state management in KVM due to:
-Introducing unnecessary XSAVE operation when switch to non-vCPU
userspace within current FPU framework.
-Forcing allocating additional space for CET supervisor states in
each thread context regardless whether it's vCPU thread or not.
Add a new helper kvm_arch_sched_out() for that purpose. Adding
the support in kvm_arch_vcpu_put/load() without the new helper
looks possible, but the put/load functions are also called in
vcpu_put()/load(), the latter are heavily used in KVM, so adding
new helper makes the implementation clearer.
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
arch/arm64/include/asm/kvm_host.h | 1 +
arch/mips/include/asm/kvm_host.h | 1 +
arch/powerpc/include/asm/kvm_host.h | 1 +
arch/riscv/include/asm/kvm_host.h | 1 +
arch/s390/include/asm/kvm_host.h | 1 +
arch/x86/kvm/x86.c | 37 +++++++++++++++++++++++++++++
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 1 +
8 files changed, 44 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7e7e19ef6993..98235cb3d258 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1023,6 +1023,7 @@ void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu);
static inline void kvm_arch_sync_events(struct kvm *kvm) {}
static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+static inline void kvm_arch_sched_out(struct kvm_vcpu *vcpu, int cpu) {}
void kvm_arm_init_debug(void);
void kvm_arm_vcpu_init_debug(struct kvm_vcpu *vcpu);
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 957121a495f0..56c5e85ba5a3 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -893,6 +893,7 @@ static inline void kvm_arch_free_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot) {}
static inline void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen) {}
static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+static inline void kvm_arch_sched_out(struct kvm_vcpu *vcpu, int cpu) {}
static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 14ee0dece853..11587d953bf6 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -880,6 +880,7 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {}
static inline void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen) {}
static inline void kvm_arch_flush_shadow_all(struct kvm *kvm) {}
static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+static inline void kvm_arch_sched_out(struct kvm_vcpu *vcpu, int cpu) {}
static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index ee0acccb1d3b..6ff4a04fe0f2 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -244,6 +244,7 @@ struct kvm_vcpu_arch {
static inline void kvm_arch_sync_events(struct kvm *kvm) {}
static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+static inline void kvm_arch_sched_out(struct kvm_vcpu *vcpu, int cpu) {}
#define KVM_ARCH_WANT_MMU_NOTIFIER
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 2bbc3d54959d..d1750a6a86cf 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -1033,6 +1033,7 @@ extern int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc);
static inline void kvm_arch_sync_events(struct kvm *kvm) {}
static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+static inline void kvm_arch_sched_out(struct kvm_vcpu *vcpu, int cpu) {}
static inline void kvm_arch_free_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot) {}
static inline void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen) {}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7a3753c05c09..f7558f0f6fc0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11212,6 +11212,33 @@ static void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
trace_kvm_fpu(0);
}
+static void kvm_save_cet_supervisor_ssp(struct kvm_vcpu *vcpu)
+{
+ preempt_disable();
+ if (unlikely(guest_can_use(vcpu, X86_FEATURE_SHSTK))) {
+ rdmsrl(MSR_IA32_PL0_SSP, vcpu->arch.cet_s_ssp[0]);
+ rdmsrl(MSR_IA32_PL1_SSP, vcpu->arch.cet_s_ssp[1]);
+ rdmsrl(MSR_IA32_PL2_SSP, vcpu->arch.cet_s_ssp[2]);
+ /*
+ * Omit reset to host PL{1,2}_SSP because Linux will never use
+ * these MSRs.
+ */
+ wrmsrl(MSR_IA32_PL0_SSP, 0);
+ }
+ preempt_enable();
+}
+
+static void kvm_reload_cet_supervisor_ssp(struct kvm_vcpu *vcpu)
+{
+ preempt_disable();
+ if (unlikely(guest_can_use(vcpu, X86_FEATURE_SHSTK))) {
+ wrmsrl(MSR_IA32_PL0_SSP, vcpu->arch.cet_s_ssp[0]);
+ wrmsrl(MSR_IA32_PL1_SSP, vcpu->arch.cet_s_ssp[1]);
+ wrmsrl(MSR_IA32_PL2_SSP, vcpu->arch.cet_s_ssp[2]);
+ }
+ preempt_enable();
+}
+
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
{
struct kvm_queued_exception *ex = &vcpu->arch.exception;
@@ -11222,6 +11249,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
kvm_sigset_activate(vcpu);
kvm_run->flags = 0;
kvm_load_guest_fpu(vcpu);
+ kvm_reload_cet_supervisor_ssp(vcpu);
kvm_vcpu_srcu_read_lock(vcpu);
if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) {
@@ -11310,6 +11338,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
r = vcpu_run(vcpu);
out:
+ kvm_save_cet_supervisor_ssp(vcpu);
kvm_put_guest_fpu(vcpu);
if (kvm_run->kvm_valid_regs)
store_regs(vcpu);
@@ -12398,9 +12427,17 @@ void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu)
pmu->need_cleanup = true;
kvm_make_request(KVM_REQ_PMU, vcpu);
}
+
+ kvm_reload_cet_supervisor_ssp(vcpu);
+
static_call(kvm_x86_sched_in)(vcpu, cpu);
}
+void kvm_arch_sched_out(struct kvm_vcpu *vcpu, int cpu)
+{
+ kvm_save_cet_supervisor_ssp(vcpu);
+}
+
void kvm_arch_free_vm(struct kvm *kvm)
{
kfree(to_kvm_hv(kvm)->hv_pa_pg);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d90331f16db1..b3032a5f0641 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1423,6 +1423,7 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu);
void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu);
+void kvm_arch_sched_out(struct kvm_vcpu *vcpu, int cpu);
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 66c1447d3c7f..42f28e8905e1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5885,6 +5885,7 @@ static void kvm_sched_out(struct preempt_notifier *pn,
{
struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
+ kvm_arch_sched_out(vcpu, 0);
if (current->on_rq) {
WRITE_ONCE(vcpu->preempted, true);
WRITE_ONCE(vcpu->ready, true);
--
2.27.0
next prev parent reply other threads:[~2023-07-21 6:10 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-21 3:03 [PATCH v4 00/20] Enable CET Virtualization Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 01/20] x86/cpufeatures: Add CPU feature flags for shadow stacks Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 02/20] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 03/20] KVM:x86: Report XSS as to-be-saved if there are supported features Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 04/20] KVM:x86: Refresh CPUID on write to guest MSR_IA32_XSS Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 05/20] KVM:x86: Initialize kvm_caps.supported_xss Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 06/20] KVM:x86: Load guest FPU state when access XSAVE-managed MSRs Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 07/20] KVM:x86: Add fault checks for guest CR4.CET setting Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 08/20] KVM:x86: Report KVM supported CET MSRs as to-be-saved Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 09/20] KVM:x86: Add common code of CET MSR access Yang Weijiang
2023-07-26 7:33 ` Chao Gao
2023-07-26 8:26 ` Yang, Weijiang
2023-07-26 13:46 ` Chao Gao
2023-07-27 6:06 ` Yang, Weijiang
2023-07-27 7:41 ` Chao Gao
2023-07-27 16:58 ` Sean Christopherson
2023-07-21 3:03 ` Yang Weijiang [this message]
2023-07-24 8:26 ` [PATCH v4 10/20] KVM:x86: Make guest supervisor states as non-XSAVE managed Chao Gao
2023-07-24 13:50 ` Yang, Weijiang
2023-07-21 3:03 ` [PATCH v4 11/20] KVM:x86: Save and reload GUEST_SSP to/from SMRAM Yang Weijiang
2023-07-24 9:13 ` Chao Gao
2023-07-24 14:16 ` Yang, Weijiang
2023-07-24 14:26 ` Sean Christopherson
2023-07-21 3:03 ` [PATCH v4 12/20] KVM:VMX: Introduce CET VMCS fields and control bits Yang Weijiang
2023-07-27 5:26 ` Chao Gao
2023-07-27 7:13 ` Yang, Weijiang
2023-07-21 3:03 ` [PATCH v4 13/20] KVM:VMX: Emulate read and write to CET MSRs Yang Weijiang
2023-07-26 8:06 ` Chao Gao
2023-07-27 3:19 ` Yang, Weijiang
2023-07-27 5:16 ` Chao Gao
2023-07-27 7:10 ` Yang, Weijiang
2023-07-27 15:20 ` Sean Christopherson
2023-07-28 0:43 ` Yang, Weijiang
2023-07-21 3:03 ` [PATCH v4 14/20] KVM:VMX: Set up interception for " Yang Weijiang
2023-07-26 8:30 ` Chao Gao
2023-07-27 3:48 ` Yang, Weijiang
2023-07-21 3:03 ` [PATCH v4 15/20] KVM:VMX: Save host MSR_IA32_S_CET to VMCS field Yang Weijiang
2023-07-26 8:47 ` Chao Gao
2023-07-26 14:05 ` Sean Christopherson
2023-07-27 7:29 ` Yang, Weijiang
2023-07-21 3:03 ` [PATCH v4 16/20] KVM:x86: Optimize CET supervisor SSP save/reload Yang Weijiang
2023-07-27 3:27 ` Chao Gao
2023-07-27 6:23 ` Yang, Weijiang
2023-07-21 3:03 ` [PATCH v4 17/20] KVM:x86: Enable CET virtualization for VMX and advertise to userspace Yang Weijiang
2023-07-27 6:32 ` Chao Gao
2023-07-27 7:26 ` Yang, Weijiang
2023-07-21 3:03 ` [PATCH v4 18/20] KVM:x86: Enable guest CET supervisor xstate bit support Yang Weijiang
2023-07-27 8:03 ` Chao Gao
2023-07-21 3:03 ` [PATCH v4 19/20] KVM:nVMX: Refine error code injection to nested VM Yang Weijiang
2023-07-21 3:03 ` [PATCH v4 20/20] KVM:nVMX: Enable CET support for " Yang Weijiang
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