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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604944771; bh=gc4v4mCeLEmNxjSK4Rq4QvjBgesKnjE95kfraj2zIz4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UP0l2FB4cQ1bmzPZIsO7BLCJWfwuCxXGaZ46IG/ucn4B1qnkhdi4uTCUWSRBqCQYW nwdENDdHOOAhIll9yTOCeh8B/Gqt9/2murGdmxWPh4kPuhFs24xIvXN1KgUiLkYxmE 4lGfBsc8fDsj9CEd+2mpfH4X3RLHtT07jFh7Dt80= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1kcBRx-009BQs-8N; Mon, 09 Nov 2020 17:59:29 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Subject: [PATCH v2 3/5] KVM: arm64: Patch kimage_voffset instead of loading the EL1 value Date: Mon, 9 Nov 2020 17:59:21 +0000 Message-Id: <20201109175923.445945-4-maz@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201109175923.445945-1-maz@kernel.org> References: <20201109175923.445945-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, alexandru.elisei@arm.com, ascull@google.com, will@kernel.org, qperret@google.com, ndesaulniers@google.com, dbrazdil@google.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201109_125932_106028_E7B9D683 X-CRM114-Status: GOOD ( 17.26 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kernel-team@android.com, Suzuki K Poulose , Will Deacon , Quentin Perret , ndesaulniers@google.com, James Morse , Andrew Scull , dbrazdil@google.com, Alexandru Elisei , Julien Thierry Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Directly using the kimage_voffset variable is fine for now, but will become more problematic as we start distrusting EL1. Instead, patch the kimage_voffset into the HYP text, ensuring we don't have to load an untrusted value later on. Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_mmu.h | 22 ++++++++++++++++++++++ arch/arm64/kernel/image-vars.h | 4 +--- arch/arm64/kvm/hyp/nvhe/host.S | 5 +---- arch/arm64/kvm/va_layout.c | 6 ++++++ 4 files changed, 30 insertions(+), 7 deletions(-) diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 608c3a83e740..400d2d73ce12 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -72,6 +72,28 @@ alternative_cb kvm_update_va_mask alternative_cb_end .endm +/* + * Convert a kernel image address to a PA + * reg: kernel address to be converted in place + * tmp: temporary register + * + * The actual code generation takes place in kvm_get_kimage_voffset, and + * the instructions below are only there to reserve the space and + * perform the register allocation (kvm_get_kimage_voffset uses the + * specific registers encoded in the instructions). + */ +.macro kimg_pa reg, tmp +alternative_cb kvm_get_kimage_voffset + movz \tmp, #0 + movk \tmp, #0, lsl #16 + movk \tmp, #0, lsl #32 + movk \tmp, #0, lsl #48 +alternative_cb_end + + /* reg = __pa(reg) */ + sub \reg, \reg, \tmp +.endm + #else #include diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index e8c194f8de88..4b32588918d9 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -65,13 +65,11 @@ __efistub__ctype = _ctype; KVM_NVHE_ALIAS(kvm_patch_vector_branch); KVM_NVHE_ALIAS(kvm_update_va_mask); KVM_NVHE_ALIAS(kvm_update_kimg_phys_offset); +KVM_NVHE_ALIAS(kvm_get_kimage_voffset); /* Global kernel state accessed by nVHE hyp code. */ KVM_NVHE_ALIAS(kvm_vgic_global_state); -/* Kernel constant needed to compute idmap addresses. */ -KVM_NVHE_ALIAS(kimage_voffset); - /* Kernel symbols used to call panic() from nVHE hyp code (via ERET). */ KVM_NVHE_ALIAS(__hyp_panic_string); KVM_NVHE_ALIAS(panic); diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index ed27f06a31ba..4e207c1c5126 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -115,10 +115,7 @@ SYM_FUNC_END(__hyp_do_panic) * Preserve x0-x4, which may contain stub parameters. */ ldr x5, =__kvm_handle_stub_hvc - ldr_l x6, kimage_voffset - - /* x5 = __pa(x5) */ - sub x5, x5, x6 + kimg_pa x5, x6 br x5 .L__vect_end\@: .if ((.L__vect_end\@ - .L__vect_start\@) > 0x80) diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c index 1d00d2cb93fd..d61117805de0 100644 --- a/arch/arm64/kvm/va_layout.c +++ b/arch/arm64/kvm/va_layout.c @@ -251,3 +251,9 @@ void kvm_update_kimg_phys_offset(struct alt_instr *alt, { generate_mov_q(kimage_voffset + PHYS_OFFSET, origptr, updptr, nr_inst); } + +void kvm_get_kimage_voffset(struct alt_instr *alt, + __le32 *origptr, __le32 *updptr, int nr_inst) +{ + generate_mov_q(kimage_voffset, origptr, updptr, nr_inst); +}