From: Fuad Tabba <tabba@google.com>
Date: Mon, 22 Jul 2024 16:33:11 +0000 (+0100)
Subject: KVM: arm64: Tidying up PAuth code in KVM
X-Git-Tag: for-6.12/io_uring-20240913~43^2^2~6
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=7e814a20f6da2bd2044b1a4682dd92a6f0df5a92;p=linux-2.6-block.git

KVM: arm64: Tidying up PAuth code in KVM

Tidy up some of the PAuth trapping code to clear up some comments
and avoid clang/checkpatch warnings. Also, don't bother setting
PAuth HCR_EL2 bits in pKVM, since it's handled by the hypervisor.

Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20240722163311.1493879-1-tabba@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---

diff --git a/arch/arm64/include/asm/kvm_ptrauth.h b/arch/arm64/include/asm/kvm_ptrauth.h
index d81bac256abc..6199c9f7ec6e 100644
--- a/arch/arm64/include/asm/kvm_ptrauth.h
+++ b/arch/arm64/include/asm/kvm_ptrauth.h
@@ -104,7 +104,7 @@ alternative_else_nop_endif
 
 #define __ptrauth_save_key(ctxt, key)					\
 	do {								\
-		u64 __val;                                              \
+		u64 __val;						\
 		__val = read_sysreg_s(SYS_ ## key ## KEYLO_EL1);	\
 		ctxt_sys_reg(ctxt, key ## KEYLO_EL1) = __val;		\
 		__val = read_sysreg_s(SYS_ ## key ## KEYHI_EL1);	\
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 23e1fa56c02d..9bef7638342e 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -522,10 +522,10 @@ void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
 
 static void vcpu_set_pauth_traps(struct kvm_vcpu *vcpu)
 {
-	if (vcpu_has_ptrauth(vcpu)) {
+	if (vcpu_has_ptrauth(vcpu) && !is_protected_kvm_enabled()) {
 		/*
-		 * Either we're running running an L2 guest, and the API/APK
-		 * bits come from L1's HCR_EL2, or API/APK are both set.
+		 * Either we're running an L2 guest, and the API/APK bits come
+		 * from L1's HCR_EL2, or API/APK are both set.
 		 */
 		if (unlikely(vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu))) {
 			u64 val;
@@ -542,16 +542,10 @@ static void vcpu_set_pauth_traps(struct kvm_vcpu *vcpu)
 		 * Save the host keys if there is any chance for the guest
 		 * to use pauth, as the entry code will reload the guest
 		 * keys in that case.
-		 * Protected mode is the exception to that rule, as the
-		 * entry into the EL2 code eagerly switch back and forth
-		 * between host and hyp keys (and kvm_hyp_ctxt is out of
-		 * reach anyway).
 		 */
-		if (is_protected_kvm_enabled())
-			return;
-
 		if (vcpu->arch.hcr_el2 & (HCR_API | HCR_APK)) {
 			struct kvm_cpu_context *ctxt;
+
 			ctxt = this_cpu_ptr_hyp_sym(kvm_hyp_ctxt);
 			ptrauth_save_keys(ctxt);
 		}
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index f59ccfe11ab9..37ff87d782b6 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -27,7 +27,6 @@
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_nested.h>
-#include <asm/kvm_ptrauth.h>
 #include <asm/fpsimd.h>
 #include <asm/debug-monitors.h>
 #include <asm/processor.h>
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 6af179c6356d..8f5c56d5b1cd 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -173,9 +173,8 @@ static void __pmu_switch_to_host(struct kvm_vcpu *vcpu)
 static bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
 	/*
-	 * Make sure we handle the exit for workarounds and ptrauth
-	 * before the pKVM handling, as the latter could decide to
-	 * UNDEF.
+	 * Make sure we handle the exit for workarounds before the pKVM
+	 * handling, as the latter could decide to UNDEF.
 	 */
 	return (kvm_hyp_handle_sysreg(vcpu, exit_code) ||
 		kvm_handle_pvm_sysreg(vcpu, exit_code));