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d=hostedemail.com; s=arc-20220608; t=1746491909; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qMPYwMIfpuqoSgY0o2X+MsaTU4fXzhxuO7gkqACpiMo=; b=B8c4D7XphrLrsXZVTazXhyPlmFnuKX2dsh2Ur9xMlEsCPPsfdSoXBnMrFKimT55LRnmZnh R7+xtJgcEvbE6sMEc2E9hHocMf2h8RbJ/r+4gznyvct9zyScRxN2oowkN/07zJwu9fmsB5 sA+N1vS4Q9kxxqFJUs6UonKcEJZhgYE= Received: from fangorn.home.surriel.com ([10.0.13.7]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.97.1) (envelope-from ) id 1uC6K6-000000000IF-3uS9; Mon, 05 May 2025 20:38:14 -0400 From: Rik van Riel To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, kernel-team@meta.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, Rik van Riel , Rik van Riel Subject: [RFC PATCH 8/9] x86/mm: use RAR for kernel TLB flushes Date: Mon, 5 May 2025 20:37:46 -0400 Message-ID: <20250506003811.92405-9-riel@surriel.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250506003811.92405-1-riel@surriel.com> References: <20250506003811.92405-1-riel@surriel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 297531C0005 X-Stat-Signature: 3akhwk5si6po8o8ysmjkamfdshmm4ski X-HE-Tag: 1746491908-547233 X-HE-Meta: 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 /m4fL3vz vxiUsDL+YBcER6K4G4MFhtLd1g5fZKwIoLdZZXR4V40HBeQLADDgX2HCMteRh5rNjPJmk6BWQU8R+/JP2vbcdjFPHuoxi5l/9htsIwWRdtXBVkevg9m/Sm1oCnEH2/BrCNCJsjvZfWaZTO6nnyR6H1z7fyRjOavbhfdiEWv7hlRjJLoGqtDncD/7Qa6NjesNtaTmFxZ6eW4wMV2F2E9vWgOY5aGzShJarbLnvjux8EIaR+PGIC5C1Np9+4GfSu15oWr3R/9XwZKxC1EkExpGNuhjQz8UTB1p222qn7Qg11v4cwZr6OmmE6VPiNg78D4sDfDgq/kGas4AxfvnTiVUS7spDZg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Rik van Riel Use Intel RAR for kernel TLB flushes, when enabled. Pass in PCID 0 to smp_call_rar_many() to flush kernel memory. Unfortunately RAR_INVPCID_ADDR excludes global PTE mappings, so only full flushes with RAR_INVPCID_ALL will flush kernel mappings. Signed-off-by: Rik van Riel --- arch/x86/mm/tlb.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 7c61bf11d472..a4f3941281b6 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include "mm_internal.h" @@ -1451,6 +1452,18 @@ static void do_flush_tlb_all(void *info) __flush_tlb_all(); } +static void rar_full_flush(const cpumask_t *cpumask) +{ + guard(preempt)(); + smp_call_rar_many(cpumask, 0, 0, TLB_FLUSH_ALL); + invpcid_flush_all(); +} + +static void rar_flush_all(void) +{ + rar_full_flush(cpu_online_mask); +} + void flush_tlb_all(void) { count_vm_tlb_event(NR_TLB_REMOTE_FLUSH); @@ -1458,6 +1471,8 @@ void flush_tlb_all(void) /* First try (faster) hardware-assisted TLB invalidation. */ if (cpu_feature_enabled(X86_FEATURE_INVLPGB)) invlpgb_flush_all(); + else if (cpu_feature_enabled(X86_FEATURE_RAR)) + rar_flush_all(); else /* Fall back to the IPI-based invalidation. */ on_each_cpu(do_flush_tlb_all, NULL, 1); @@ -1487,15 +1502,36 @@ static void do_kernel_range_flush(void *info) struct flush_tlb_info *f = info; unsigned long addr; + /* + * With PTI kernel TLB entries in all PCIDs need to be flushed. + * With RAR the PCID space becomes so large, we might as well flush it all. + * + * Either of the two by itself works with targeted flushes. + */ + if (cpu_feature_enabled(X86_FEATURE_RAR) && + cpu_feature_enabled(X86_FEATURE_PTI)) { + invpcid_flush_all(); + return; + } + /* flush range by one by one 'invlpg' */ for (addr = f->start; addr < f->end; addr += PAGE_SIZE) flush_tlb_one_kernel(addr); } +static void rar_kernel_range_flush(struct flush_tlb_info *info) +{ + guard(preempt)(); + smp_call_rar_many(cpu_online_mask, 0, info->start, info->end); + do_kernel_range_flush(info); +} + static void kernel_tlb_flush_all(struct flush_tlb_info *info) { if (cpu_feature_enabled(X86_FEATURE_INVLPGB)) invlpgb_flush_all(); + else if (cpu_feature_enabled(X86_FEATURE_RAR)) + rar_flush_all(); else on_each_cpu(do_flush_tlb_all, NULL, 1); } @@ -1504,6 +1540,8 @@ static void kernel_tlb_flush_range(struct flush_tlb_info *info) { if (cpu_feature_enabled(X86_FEATURE_INVLPGB)) invlpgb_kernel_range_flush(info); + else if (cpu_feature_enabled(X86_FEATURE_RAR)) + rar_kernel_range_flush(info); else on_each_cpu(do_kernel_range_flush, info, 1); } -- 2.49.0