linux-kernel - [PATCH 1/2] KVM: arm64: pkvm: Drop unnecessary FP/SIMD trap handler

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Message-Id: <20220509162559.2387784-2-oupton@google.com>
Date:   Mon,  9 May 2022 16:25:58 +0000
From:   Oliver Upton <oupton@...gle.com>
To:     kvmarm@...ts.cs.columbia.edu
Cc:     kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, maz@...nel.org, james.morse@....com,
        alexandru.elisei@....com, suzuki.poulose@....com, tabba@...gle.com,
        qperret@...gle.com, will@...nel.org,
        Oliver Upton <oupton@...gle.com>
Subject: [PATCH 1/2] KVM: arm64: pkvm: Drop unnecessary FP/SIMD trap handler

The pVM-specific FP/SIMD trap handler just calls straight into the
generic trap handler. Avoid the indirection and just call the hyp
handler directly.

Note that the BUILD_BUG_ON() pattern is repeated in
pvm_init_traps_aa64pfr0(), which is likely a better home for it.

No functional change intended.

Signed-off-by: Oliver Upton <oupton@...gle.com>
---
 arch/arm64/kvm/hyp/nvhe/switch.c | 19 +------------------
 1 file changed, 1 insertion(+), 18 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 6410d21d8695..3dee2ad96e10 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -175,23 +175,6 @@ static bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code)
 		kvm_handle_pvm_sysreg(vcpu, exit_code));
 }
 
-/**
- * Handler for protected floating-point and Advanced SIMD accesses.
- *
- * Returns true if the hypervisor has handled the exit, and control should go
- * back to the guest, or false if it hasn't.
- */
-static bool kvm_handle_pvm_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
-{
-	/* Linux guests assume support for floating-point and Advanced SIMD. */
-	BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_FP),
-				PVM_ID_AA64PFR0_ALLOW));
-	BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_ASIMD),
-				PVM_ID_AA64PFR0_ALLOW));
-
-	return kvm_hyp_handle_fpsimd(vcpu, exit_code);
-}
-
 static const exit_handler_fn hyp_exit_handlers[] = {
 	[0 ... ESR_ELx_EC_MAX]		= NULL,
 	[ESR_ELx_EC_CP15_32]		= kvm_hyp_handle_cp15_32,
@@ -207,7 +190,7 @@ static const exit_handler_fn pvm_exit_handlers[] = {
 	[0 ... ESR_ELx_EC_MAX]		= NULL,
 	[ESR_ELx_EC_SYS64]		= kvm_handle_pvm_sys64,
 	[ESR_ELx_EC_SVE]		= kvm_handle_pvm_restricted,
-	[ESR_ELx_EC_FP_ASIMD]		= kvm_handle_pvm_fpsimd,
+	[ESR_ELx_EC_FP_ASIMD]		= kvm_hyp_handle_fpsimd,
 	[ESR_ELx_EC_IABT_LOW]		= kvm_hyp_handle_iabt_low,
 	[ESR_ELx_EC_DABT_LOW]		= kvm_hyp_handle_dabt_low,
 	[ESR_ELx_EC_PAC]		= kvm_hyp_handle_ptrauth,
-- 
2.36.0.512.ge40c2bad7a-goog